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A circle has a circumference of 48 pi centimeters, if the radius of the circle is multiplied by 9, what is the circumference of the new circle?

Any help would be appreciated.

User Pattmorter
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2 Answers

4 votes

Answer:c. 432

Step-by-step explanation: i took the test hope this helps

User Sathish Gadde
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6 votes

Answer:

C = 1357.16802635

Explanation:

So we are told that 48π = Circumference

We know that 2πr is also equal to the circumference.

Therefore we can see that the diameter (half the circumference) is equal to 48. Since the radius is half the size of the diameter, we will have to divide the diameter (48) by 2.

48/2 = 24

Our radius is 24.

We are told to multiply the radius by 9.

24 x 9 = 216

New radius = 216

Now we need to solve for the circumference again with our new radius.

C = 2πr

Plug in 216 for the radius

C = 2π(216)

Multiply the radius by 2 according to the circumference formula

C = 432π

Multiply our diameter of 432 by pi

C = 1357.16802635

We can round if we need to

C ≈ 1357 cm

User Wohops
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