# Math 7 - NYS Math Exam Review Help!

19. The circumference of the circle below is 25.12 centimeters
***** There is a circle and then there is a line and written radius
C = 2(pi)r

Which is the best estimate for the length of the radius of the circle?
a) 3 cm
b) 4 cm
c) 8 cm
d) 16 cm
please help i tried to solve this problem and I'm struggling (I'm NOT lying)
but i think the answer is b idk ..... I'm not guessing thought
I know haft of 25.12 is 12.56.

Please help

thank you

1. 👍
2. 👎
3. 👁
1. The formula for the circumference of a circle is:

C = pi * 2r

25.12 = 3.14 * 2r

25.12/3.14 = 2r

8 = 2r

8/2 = r

4 = r

1. 👍
2. 👎
👤
Ms. Sue
2. pi = 3.14

2 pi = 6.28

C = 2 r pi

25.12 = 2 r pi Divide both sides by 2 pi

25.12 / 2 pi = r

r = 25.12 / 2 pi

r = 25.12 / 6.28

r = 4 cm

1. 👍
2. 👎
3. Thank You Ms. Sue! :)

Now I understand because I didn't learn this yet in math since we are behind in our curriculum. I'm going to rewrite this so that I way I can use this to study for the exam. I'm going to post more problems (don' worry not too much). I left some geometry questions (about 2) and other problems that I need help with (don't worry it's about 4 more problems or 3 that I'm going to post). Some questions are homework checks to see if I'm correct.

thanks again :)

1. 👍
2. 👎
4. thanks Bosnian

1. 👍
2. 👎

## Similar Questions

1. ### AP Calculus

The radius of a circle is decreasing at a constant rate of 0.1 centimeters per second. In terms of the circumference C, what is the rate of the area of the circle, in square centimeters per second? a. -(0.2)pie C b. -(0.1)C c.

2. ### MATH

Find the circumference for the circle ( use 3.14 for pi ). Round to the nearest tenth. the circumference for the circle is 23 yd.

3. ### Math

Find the circumference of the circle. Round to the nearest tenth. The middle of the circle is 44mm

4. ### math

The circumference of a circle is 32 centimeters. Which is closest to the radius? A. 10.2 centimeters B. 5.1 centimeters C. 16 centimeters D. 5.3 centimeters

1. ### Math

So my question is find the circumference of the circle in terms of Pi then use the approximation 3.14 for pi and approximate the circumference. How would I do this? The radius of the circle is 2m.

2. ### Calculus (check my work)

The measurement of the circumference of a circle is found to be 64 centimeters, with a possible error of 0.9 centimeter. Approximate the percent error in computing the area of the circle. MY ANSWER 8.83%

3. ### Math

Find the circumference of the circle. Round your answer to the nearest hundredth. Use 3.14 or 227 for π. Its a circle with 3 feet in the middle

4. ### math

A regular hexagon is drawn inside of a circle so that each of its vertices touches the circle. The diameter of the circle is 4 centimeters and the perimeter of the hexagon is 12 centimeters. How much longer is the circumference of

1. ### Math

The area of a circle is given by the expression pi(16x^2 - 40x + 25) . a) What is the diameter of the circle? b) What is its circumference?

2. ### algebra

The circle has a circumference of 50.24. Using 3.14 to approximate piâ€‹, find the value of x. â€ƒâ€ƒâ€ƒâ€ƒâ€ƒâ€ƒA circle with a radius labeled x plus 3. x + 3

3. ### math

Find the circumference of the circle. Use 3.14 for π. Round to the nearest hundredth, if necessary. 7 in. The circumference of the circle is about inches.

4. ### Math

One medium circle and one small circle touch each other, and each circle touches the larger circle. The figure shows two circles of different radius inscribed in a larger circle. The two circles are drawn such that both touch the