alexis rode her bike 4.5 miles. johnny rode his bike 8.1 miles. how many more miles did johnny ride his bike?

I need long division

Class 1 wiring is required to exceed standards for power and lighting wiring. Class 3 wiring is functionally similar to Class 2 wiring, but with higher voltage and power limitations.

It should be noted that a Class 2 circuit associated with the electrical equipment that is part of a residential oil furnace, for example, usually receives power from a 24-V transformer whose primary connects to a 120-V premises branch circuit.

In conclusion, a class 1 must sit in metal or non-metallic raceway or be metal-sheathed wiring as compared to jacketed cable such as type NM.

Learn more about wiring on

https://brainly.com/question/24786034

#SPJ1

Electricians know about Class 1, 2, and 3 wiring because these terms are spelled out in the National Electrical Code. Electronics engineers, however, tend to be in the dark about these terms. So here is a short primer on classes of wiring for the curious.

The NEC in Article 725 makes a sharp distinction between wiring for “ordinary” power and light circuits and specialized circuits where the power and/or voltage is limited. These circuits are designated Class 1, 2 and 3, not to be confused with the Class I, II and III hazardous locations – an entirely different matter. Class 1, 2 and 3 circuits are defined primarily in terms of the power supply to which they are connected. Power supplies are generally batteries, transformers or electronic power supplies. When working on an existing installation, it is a simple matter of identifying the power source and checking its marking. A Class 2 circuit associated with the electrical equipment that is part of a residential oil furnace, for example, usually receives power from a 24-V transformer whose primary connects to a 120-V premises branch circuit. The relatively high impedance of this small device ensures that its voltage and power output will be in the Class 2 range. Such a device will be marked as suitable as a Class 2 power source. Describe how the results from Class 1, Class 2, and Class 3 differ.

a) If t is a real variable, then the line through the endpoints of p and q is

(p - q) t + p

That is, p - q is the vector pointing from the tip of q to the tip of p (recall the "triangle law" for vector addition). Then (p - q) t is a line through the origin parallel to p - q. Adding p to this line translates it so that it will pass through p.

So one formulation of the line's equation is

r(t) = ((3, -1, 1) - (7, 1, 3)) t + (3, -1, 1)

… = (-4, -2, -2) t + (3, -1, 1)

… = (-4t + 3, -2t - 1, -2t + 1)

which is identical to the equation you found, with t = -k.

b) OA is the line segment connecting the origin O and the point A on the line we found in part (a).

a is then the vector pointing from the origin to A. If OA is perpendicular to the line, then the dot product of a with the direction vector p - q must be zero.

a • (p - q) = 0

(a₁, a₂, a₃) • (-4, -2, -2) = 0

-4a₁ - 2a₂ - 2a₃  =0

2a₁ + a₂ + a₃ = 0

Let s(t) denote the line containing a. Then

s(t) = (a₁, a₂, a₃) t

r(t) and s(t) intersect exactly once for some value of t such that

(a₁, a₂, a₃) t = (-4, -2, -2) t + (3, -1, 1)

(a₁ + 4, a₂ + 2, a₃ + 2) t = (3, -1, 1)

Now we solve for the components of a such that the conditions we found are all met:

\(\begin{cases}2a_1 + a_2 + a_3 = 0 \\ (a_1 + 4)t = 3 \\ (a_2 + 2)t = -1 \\ (a_3 + 2)t = 1\end{cases}\)

and you would find the two lines intersect when t = 1/2, and so

a = (2, -4, 0)

The answer of the following are; A. 16 yellow marbles were chosen

B. 24 marbles were chosen

C. Not enough information.

Multiplication is the mathematical operation that is used to determine the product of two or more numbers. If an event can occur in m different ways and if following it, a second event can occur in n different ways, then the two events in succession can occur in m × n different ways.

We are obtained data from the question. This include the following:

marble = 40

Black marble =..?

A. From the question given, 3/5 of the 40 marbles were chosen. It therefore means that 2/5 were not chosen and 16 of these were black.

yellow marble chosen = 2/5 x 40 = 16.

Therefore, 16 yellow marbles were chosen.

B. From the question given, 3/5 of the 40 marbles were chosen.

marble chosen = 3/5 x 40 = 24.

Therefore, 24 marbles were chosen.

C. Not enough information because the number of black marbles in the bag was not given, we can not obtain the total number of marbles that were not chosen.

Learn more about multiplications;

https://brainly.com/question/14059007

#SPJ1

Answer:

hello your question is incomplete attached below is the complete question

estimating: Ft( -15,40 ) = ( 1.2 + 1.4 ) / 2 = 1.30⁰c

when the actual temperature is -15⁰c and the wind speed is 40 km/h the apparent temperatures increase by 1.3⁰c  that the actual temperature rises

estimating:  Fv ( -15,40 ) = (-0.2 + -0.1 ) / 2 = -0.15⁰c

when the actual temperature -15⁰c and the wind speed is 40 km/h the apparent temperature decreases by about 0.15⁰c for every km/h that the wind speed

Step-by-step explanation:

A) Estimating the values of Ft(−15, 40) and fv(−15, 40)

attached below is a detailed solution

To estimate the value of Ft( -15,40 ) we have to take an average value hence Ft ( -15,40 ) = ( 1.2 + 1.4 ) / 2 = 1.30

and this means that when the actual temperature is -15⁰c and the wind speed is 40 km/h the apparent temperatures increase by 1.3⁰c  that the actual temperature rises

To estimate the value of Fv(-15,40 )  we have to take an average value

hence Fv ( -15,40 ) = (-0.2 + -0.1 ) / 2 = -0.15

and this means that when the actual temperature -15⁰c and the wind speed is 40 km/h the apparent temperature decreases by about 0.15⁰c for every km/h that the wind speed

Answer:Your answer would be -8 x - 17 y

Step-by-step explanation: x - 9 x would be - 8 x

                                               You would have to distribute the negative in the problem -(9 x- 8 y) which would make it -9 x +8 y and 9 y + 8 y is 17 y so there fore the answer is -8 x - 17 y

The area of the wooden part of the frame is 4x² +20x +17 sq.cm , Area of a Rectangle is 4x² +2x-2 sq.cm .

A rectangle is a polygon with four sides . The opposite sides are parallel and equal.

It is given that the outside length and breadth is 4x + 5 centimeters and width 2x + 3 centimeters.

inside the frame has length and breadth 4x - 2 centimeters long and x + 1 centimeters wide.

The polynomial to describe the area of the picture window

The dimension of the inner picture frame is the dimension of the picture window

Area of a Rectangle = Length *  Breadth

Area of a Rectangle = (4x-2) (x+1) = 4x² +4x -2x-2 = 4x² +2x-2 sq.cm

The picture frame area without the window =

Area of the total picture frame - Area of the inner picture frame

= (4x+5)(2x+3) - (4x-2)(x+1)

= 8x² + 12x +10x+15 -4x²-2x +2

= 4x² +20x +17

The area of the wooden part of the frame is 4x² +20x +17 .

To know more about Rectangle

https://brainly.com/question/12394910

#SPJ1

The amount deposited in an account that pays 3% and 7% of interest will be $225 and $775, respectively. Then the correct option is D.

The amount of any product is given as though it was a proportion of a hundred. The ratio can be expressed as a quarter of 100. The phrase % translates for one hundred percent. It is symbolized by the character '%'.

The percentage is given as,

Percentage (P) = [Final value - Initial value] / Initial value x 100

You have $1000 to put resources into two distinct records. To set aside the cash you really want for school, you really want to average a 6.1 percent premium. Assuming the two records pay a 3% and 7 % premium.

Let 'x' be the amount deposited in an account that pays 3% of interest. Then the amount deposited in another account that pays 7% of interest is (1000 - x). Then the equation is given as,

0.03x + 0.07(1000 - x) = 0.061 × 1000

Simplify the equation, then we have

0.03x + 0.07(1000 - x) = 0.061 × 1000

0.03x + 70 - 0.07x = 61

-0.04x + 70 = 61

0.04x = 70 - 61

0.04x = 9

x = 9 / 0.04

x = $225

Then the amount in the second account will be given as,

⇒ $1000 - $225

⇒ $775

The amount deposited in an account that pays 3% and 7% of interest will be $225 and $775, respectively. Then the correct option is D.

More about the percentage link is given below.

https://brainly.com/question/8011401

#SPJ1

The sequence for the given situation is:

y (number of people who know about the soft opening

y0: number of people who know about the soft opening at day 0

As each person will tell 2 people about the soft opening you multiply the number of people of previous dat (y(x-1)) by 2 and add to it the initial number of people (1).

Then, the data in the table is find using the formula of the sequence above:

The calculated value of x in the equation (x + 1) (x - 5) = 16 is 7

From the question, we have the following parameters that can be used in our computation:

(x + 1) (x - 5) = 16

The above expression is the product of two factors

(x + 1) and (x - 5)

And the result is 16

Express 16 as 8 * 2

So, we have

(x + 1) (x - 5) = 8 * 2

By comparison, we have

x + 1 = 8 and x - 5 = 2

When evaluated, we have

x = 7 and x = 7

This means that the value of x in the equation is 7

Read more about equation at

https://brainly.com/question/148035

#SPJ1

By using these mental math techniques, Allie can quickly estimate that the discounted price of the hat is approximately $8.50. Allie can use mental math strategies to calculate the discounted price of the hat without a calculator or paper.

Here are a few ways she can do it:

Method 1: Percentage off

Calculate 10% of $12.99 by moving the decimal point one place to the left: $1.29.

Divide 10% by 2 to get 5%: $1.29 / 2 = $0.64.

Multiply 5% by 7 to get 35%: $0.64 * 7 = $4.48.

Subtract $4.48 from $12.99: $12.99 - $4.48 = $8.51 (approximate).

Method 2: Amount saved

Calculate 35% of $12.99 by multiplying the original price by 35% (0.35): $12.99 * 0.35 = $4.55.

Subtract $4.55 from $12.99: $12.99 - $4.55 = $8.44 (approximate).

Method 3: Estimation

Round $12.99 to $13 for easier calculations.

Estimate 35% of $13 to be approximately $4.50.

Subtract $4.50 from $13: $13 - $4.50 = $8.50 (approximate).

For more such questions on Techniques:

https://brainly.com/question/13982807

#SPJ8

Answer:

6

Step-by-step explanation:

do the highest common factor of both

which is 6

Answer:

Renaissance Naturalism

Step-by-step explanation:

just took the quiz

Answer:

m∠1 = 58°

m∠2 = 58°

m∠3 = 72°

Step-by-step explanation:

The sum of the interior angles of a triangle is equal to 180°. The vertical angles at Point Z are congruent and therefore their measures are equal.

Answer: 5/6

Step-by-step explanation:

Answer:

6 divided by 8 is 3/4 (.78)

2/3 divided by 8 is 1/12 (0.083)

6 2/3 divided by 8 is 5/6 (0.83)

f(3x - 1) = 6x - 1

Rewrite 6x - 1 as a function of 3x - 1:

6x - 1 = 6x - 2 + 1 = 2(3x - 1) + 1

That is,

f(3x - 1) = 2(3x - 1) + 1

which means

f(x) = 2x + 1

and so

f(0) = 2*0 + 1 = 1

The value of the experimental probability of tossing heads is,

⇒ 1 / 3

We have to given that;

Coin Toss Results: T, H, T, H, T, H, T, T, T, T, H, T, H, T, T

Where, H stands for heads and T stands for Tails.

Hence, Total outcomes = 15

And, Head outcomes = 5

Thus, The value of the experimental probability of tossing heads is,

⇒ 5 / 15

⇒ 1 / 3

Learn more about the probability visit:

https://brainly.com/question/13604758

#SPJ1

Answer:

$828.53

Step-by-step explanation:

The formula is: A = P(1 + r/k)^(kt)

A = 750(1 + 0.02/12)^(12*5)

A = 750(1 + 0.00166667)^60

A = 750(1.00166667)^60

A = 750(1.104713)

A = $828.53 (rounded to the nearest cent)

So, the accumulated amount after 5 years with a 2% interest rate compounded monthly is $828.53.

Emilio can find that the critical value t* for a 90% confidence level and 11 degrees of freedom is approximately 1.796.

To construct a t interval for the mean lifespan with 90% confidence, Emilio needs to use a t-distribution with n-1 degrees of freedom. The confidence interval for the population is given by:

confidence interval = x ± t × (s·x/√n)

Where x is the sample mean, s·x is the sample standard deviation, n is the sample size, and t is the critical value of the t-distribution.

Since the sample size is n=12, the degrees of freedom for the t-distribution will be (n-1) = 11. To find the critical value t* for a 90% confidence level and 11 degrees of freedom, Emilio can use a t-distribution table or a statistical software.

Using a t-distribution table or calculator, Emilio can find that the critical value t* for a 90% confidence level and 11 degrees of freedom is approximately 1.796.

To know more about  standard deviation, visit:

https://brainly.com/question/28528375

#SPJ1

Answer:

Matrix :

\(\begin{bmatrix}1&1&1&|&380\\ 5&3&10&|&1460\\ -2&1&0&|&0\end{bmatrix}\)

Solution Set : { x = 123, y = 246, z = 11 }

Step-by-step explanation:

Let's say that x represents the number of car wash tickets, y represents the number of silly sting fight tickets, and z represents the number of dance tickets. We know that the total tickets = 380, so therefore,

x + y + z = 380,

And the car wash tickets were $5 each, the silly sting fight tickets were $3 each and the dance tickets were $10 each, the total cost being $1460.

5x + 3y + 10z = 1460

The silly string tickets were sold for twice as much as the car wash tickets.

y = 2x

Therefore, if we allign the co - efficients of the following system of equations, we get it's respective matrix.

System of Equations :

\(\begin{bmatrix}x+y+z=380\\ 5x+3y+10z=1460\\ y=2x\end{bmatrix}\)

Matrix :

\(\begin{bmatrix}1&1&1&|&380\\ 5&3&10&|&1460\\ -2&1&0&|&0\end{bmatrix}\)

Let's reduce this matrix to row - echelon form, receiving the number of car wash tickets, silly sting fight tickets, and dance tickets,

\(\begin{bmatrix}5&3&10&1460\\ 1&1&1&380\\ -2&1&0&0\end{bmatrix}\) - Swap Matrix Rows

\(\begin{bmatrix}5&3&10&1460\\ 0&\frac{2}{5}&-1&88\\ -2&1&0&0\end{bmatrix}\) - Cancel leading Co - efficient in second row

\(\begin{bmatrix}5&3&10&1460\\ 0&\frac{2}{5}&-1&88\\ 0&\frac{11}{5}&4&584\end{bmatrix}\) - Cancel leading Co - efficient in third row

\(\begin{bmatrix}5&3&10&1460\\ 0&\frac{11}{5}&4&584\\ 0&\frac{2}{5}&-1&88\end{bmatrix}\) - Swap second and third rows

\(\begin{bmatrix}5&3&10&1460\\ 0&\frac{11}{5}&4&584\\ 0&0&-\frac{19}{11}&-\frac{200}{11}\end{bmatrix}\) - Cancel leading co - efficient in row three

And we can continue, canceling the leading co - efficient in each row until this matrix remains,

\(\begin{bmatrix}1&0&0&|&\frac{2340}{19}\\ 0&1&0&|&\frac{4680}{19}\\ 0&0&1&|&\frac{200}{19}\end{bmatrix}\)

x = 2340 / 19 = ( About ) 123 car wash tickets sold, y= 4680 / 19 =( About ) 246 silly string fight tickets sold, z = 200 / 19 = ( About ) 11 tickets sold

Answer:

A=-2 and f(A)=10

Step-by-step explanation:

\(det\left[\begin{array}{cc}a&b\\c&d\end{array}\right] =ac-bd\)

therefore

\(det\left[\begin{array}{cc}1&2\\3&4\end{array}\right] =(1)(4)-(2)(3)=4-6=-2\)

now evaluate \(f(-2)\)

\(f(x)=2x^2-6x-10\)

\(f(-2)=2(-2)^2-6(-2)-10\)

\(f(-2)=2(4)+12-10\)

\(f(-2)=8+2\)

\(f(-2)=10\)

Answer:

A=-2 and f(A)=10

Step-by-step explanation:

therefore

now evaluate

Answer:

The first step is to label the points being (1,2.3),(6,6.8) in which the first ordered pairs is the number of weeks, and the second one is the dollars in millions.

Hence, the slope is: m=(6.8-2.3)/(6-1) = 4.5/5 = 9/10 = 0.9

The slope represents the dollar rate in the millions per week. In this case, the movie grossed $0.9 million per week from week one to the sixth week.

Answer:

Fourth option: y = 2/5x - 3

Step-by-step explanation:

it is perpendicular :)

Answer:

Your answer y=-5/2x + 6

Mark it as brainlist answer. As soon as possible.

Step-by-step explanation:

Let's solve the given questions step by step:

1. Determine the equation of f:

From the given information, we know that the turning point of f is (1, 4). The general form of a quadratic function is f(x) = ax^2 + bx + c. We are given that f(x) = a(x + p)^2 + q, so let's substitute the values:

f(x) = a(x + p)^2 + q

Since the turning point is (1, 4), we can substitute x = 1 and f(x) = 4 into the equation:

4 = a(1 + p)^2 + q

This gives us one equation involving a, p, and q.

2. Determine the equation of g:

The equation of g is given as g(x) = 0.3x + p1.

3. Determine the coordinates of the x-intercept of g:

The x-intercept is the point where the graph of g intersects the x-axis. At this point, the y-coordinate is 0.

Setting g(x) = 0, we can solve for x:

0 = 0.3x + p1

-0.3x = p1

x = -p1/0.3

Therefore, the x-intercept of g is (-p1/0.3, 0).

4. For which values of x will f(x) ≥ g(x)?

To determine the values of x where f(x) is greater than or equal to g(x), we need to compare their expressions.

f(x) = a(x + p)^2 + q

g(x) = 0.3x + p1

We need to find the values of x for which f(x) ≥ g(x):

a(x + p)^2 + q ≥ 0.3x + p1

Simplifying the equation will involve expanding the square and rearranging terms, but since the equation involves variables a, p, and q, we cannot determine the exact values without further information or constraints.

To summarize:

We have determined the equation of f in terms of a, p, and q, and the equation of g in terms of p1. We have also found the coordinates of the x-intercept of g. However, without additional information or constraints, we cannot determine the exact values of a, p, q, or p1, or the values of x for which f(x) ≥ g(x).

The linear function which represents a slope of -3 as required in the task content is; A two column table with five rows. The first column, x, has the entries, negative 5, negative 1, 3, 7. The second column, y, has the entries, 32, 24, 16, 8.

It follows that the task requires that a linear function whose slope, i.e rate of change is -2 is to be determined.

Since slope is the rate of change in y with respect to x;

The required linear function is; A two column table with five rows. The first column, x, has the entries, -5, -1, 3, 7. The second column, y, has the entries, 32, 24, 16, 8 so that we have;

Slope = (24 - 32) / (-1 -(-5)) = -8 / 4 = -2.

Remarks: The complete question is such that the required slope is -2.

Read more on slope of a linear function;

https://brainly.com/question/28702168

#SPJ1

Answer: the second option

Step-by-step explanation:

i took the assignment

Answer:

Sara is taller than Michael

Step-by-step explanation:

From the question, Sara tells Michael she is 160 centimeters tall, that is

Sara's height is 160 centimeters.

and Michael says he is 60 inches tall, that is

Michael's height is 60 inches.

To determine who is taller among Sarah and Michael, we will have to compare their heights in the same unit.

Lets compare the heights in centimeters,

Sara's height is in centimeters, then

We will have to convert Michael's height from inches to centimeters

From the question, If there are 2.54 centimeters in an inch, that is

1 inch = 2.54 centimeters

Then 60 inches = 60 × 2.54 centimeters

= 152.4 centimeters

Hence, Michael's height in centimeters is 152.4 centimeters

Since Sara is 160 centimeters tall, then Sara is taller than Michael.

Amelia uses 99 balls of yarn in all to make the sweaters and scarves.

What is addition ?

Addition is a basic mathematical operation that combines two or more quantities to find a total or a sum. It is denoted by the symbol "+" and is usually taught in elementary school. In addition, the order of the numbers does not matter, meaning that you can add them in any order and still get the same result. For example, 3 + 5 is the same as 5 + 3, and the answer is 8 in both cases.

According to the question:
To find the total number of balls of yarn that Amelia uses, we can start by finding the total number of balls of yarn she uses to make the sweaters and scarves separately, and then add those amounts together.

To make 7 sweaters, Amelia uses 7 x 9 = 63 balls of yarn.

To make 9 scarves, Amelia uses 9 x 4 = 36 balls of yarn.

Adding these together, we get:

63 + 36 = 99

So, Amelia uses 99 balls of yarn in all to make the sweaters and scarves.

To know more about addition visit:
https://brainly.com/question/29560851
#SPJ1

heightAnswer:

12

Step-by-step explanation:

(x representing the smallest size)

x + 4x = 60

5x = 60

x = 12

the height is 12

to confirm:

12 x 4 = 48

48 + 12 = 60

Answer:

The answer is 16pi or 50.3cm² to 1 d.p

Step-by-step explanation:

The non shaded=area of shaded

d=8

r=d/2=4

A=pir³

A=p1×4²

A=pi×16

A=16picm² or 50.3cm² to 1d.p

Answer:

3.45 cm (3 s.f.)

Step-by-step explanation:

We have been given a 5-sided regular polygon inside a circumcircle. A circumcircle is a circle that passes through all the vertices of a given polygon. Therefore, the radius of the circumcircle is also the radius of the polygon.

To find the radius of a regular polygon given its side length, we can use this formula:

\(\boxed{\begin{minipage}{6 cm}\underline{Radius of a regular polygon}\\\\$r=\dfrac{s}{2\sin\left(\dfrac{180^{\circ}}{n}\right)}$\\\\\\where:\\\phantom{ww}$\bullet$ $r$ is the radius.\\ \phantom{ww}$\bullet$ $s$ is the side length.\\\phantom{ww}$\bullet$ $n$ is the number of sides.\\\end{minipage}}\)

Substitute the given side length, s = 8 cm, and the number of sides of the polygon, n = 5, into the radius formula to find an expression for the radius of the polygon (and circumcircle):

\(\begin{aligned}\implies r&=\dfrac{8}{2\sin\left(\dfrac{180^{\circ}}{5}\right)}\\\\ &=\dfrac{4}{\sin\left(36^{\circ}\right)}\\\\ \end{aligned}\)

The formulas for the area of a regular polygon and the area of a circle given their radii are:

\(\boxed{\begin{minipage}{6 cm}\underline{Area of a regular polygon}\\\\$A=\dfrac{nr^2\sin\left(\dfrac{360^{\circ}}{n}\right)}{2}$\\\\\\where:\\\phantom{ww}$\bullet$ $A$ is the area.\\\phantom{ww}$\bullet$ $r$ is the radius.\\ \phantom{ww}$\bullet$ $n$ is the number of sides.\\\end{minipage}}\)

\(\boxed{\begin{minipage}{6 cm}\underline{Area of a circle}\\\\$A=\pi r^2$\\\\where:\\\phantom{ww}$\bullet$ $A$ is the area.\\\phantom{ww}$\bullet$ $r$ is the radius.\\\end{minipage}}\)

Therefore, the area of the regular pentagon is:

\(\begin{aligned}\textsf{Area of polygon}&=\dfrac{5 \cdot \left(\dfrac{4}{\sin\left(36^{\circ}\right)}\right)^2\sin\left(\dfrac{360^{\circ}}{5}\right)}{2}\\\\&=\dfrac{5 \cdot \left(\dfrac{4}{\sin\left(36^{\circ}\right)}\right)^2\sin\left(72^{\circ}\right)}{2}\\\\&=\dfrac{\dfrac{80\sin\left(72^{\circ}\right)}{\sin^2\left(36^{\circ}\right)}}{2}\\\\&=\dfrac{40\sin\left(72^{\circ}\right)}{\sin^2\left(36^{\circ}\right)}\\\\&=110.110553...\; \sf cm^2\end{aligned}\)

The area of the circumcircle is:

\(\begin{aligned}\textsf{Area of circumcircle}&=\pi \left(\dfrac{4}{\sin\left(36^{\circ}\right)}\right)^2\\\\&=\dfrac{16\pi}{\sin^2\left(36^{\circ}\right)}\\\\&=145.489779...\; \sf cm^2\end{aligned}\)

The area of the shaded area is the area of the circumcircle less the area of the regular pentagon plus the area of the small central circle.

The area of the unshaded area is the area of the regular pentagon less the area of the small central circle.

Given the shaded area is equal to the unshaded area:

\(\begin{aligned}\textsf{Shaded area}&=\textsf{Unshaded area}\\\\\sf Area_{circumcircle}-Area_{polygon}+Area_{circle}&=\sf Area_{polygon}-Area_{circle}\\\\\sf 2\cdot Area_{circle}&=\sf 2\cdot Area_{polygon}-Area_{circumcircle}\\\\2\pi r^2&=2 \cdot \dfrac{40\sin\left(72^{\circ}\right)}{\sin^2\left(36^{\circ}\right)}-\dfrac{16\pi}{\sin^2\left(36^{\circ}\right)}\\\\2\pi r^2&=\dfrac{80\sin\left(72^{\circ}\right)}{\sin^2\left(36^{\circ}\right)}-\dfrac{16\pi}{\sin^2\left(36^{\circ}\right)}\\\\\end{aligned}\)

                                                 \(\begin{aligned}2\pi r^2&=\dfrac{80\sin\left(72^{\circ}\right)-16\pi}{\sin^2\left(36^{\circ}\right)}\\\\r^2&=\dfrac{40\sin\left(72^{\circ}\right)-8\pi}{\pi \sin^2\left(36^{\circ}\right)}\\\\r&=\sqrt{\dfrac{40\sin\left(72^{\circ}\right)-8\pi}{\pi \sin^2\left(36^{\circ}\right)}}\\\\r&=3.44874763...\sf cm\end{aligned}\)

Therefore, the radius of the small circle is 3.45 cm (3 s.f.).