Question

Suppose the diameter of a circle is 9. What is its circumference?

Answer 1

If you could give the answer in terms of pi that'd be great.

Answer 2

Well we must first find the radius of the circle. The radius is half of the diameter, so our radios os 4.5

r = 4.5

Formula to find the Circumference:

\(2\pi*4.5\)

Answer 3

\(C~=~2\pi*4.5\)

Answer 4

circumference equals pi times the diameter.

Answer 5

Do you know what to do next?

And the circumference equals pi times the radius, not the diameter

Answer 6

circumference is 28.26

Answer 7

Thanks. Could you help me with a few more?

Answer 8

Just multiply 4.5 by 2, so what is 4.5 x 2?

Answer 9

9pi, I know.

Answer 10

\(C~=~9\pi\)

Or

\(C~=~9*3.14\)

Answer 11

Can you help me with a few more please?

Answer 12

Sure I can try :)

Answer 13

I might take a bit to answer here and there.. I am doing a test right now :(

Answer 14

Suppose the circumference of a circle is 15π. What is its diameter?

Answer 15

Those question marks are supposed to be pi. |:(

Answer 16

I don't know, it's not multiple choice and gives practically no info on how to answer.

Answer 17

C = 2pi*r

47.1 = 6.28*r

Now we must find the raduis to find the diameter. To do so we must divide 6.28 on both sides of the equation.

47.1/6.28 = 6.28*r/6.28

47.1/6.28 = r

What is 47.1/6.28?

Answer 18

15pi = 47.1, sorry I completely skipped a step >_<
And 2*pi = 6.28

Answer 19

After you find out what is 47.1/6.28 you multiply the answer by 2, since the radius is half of the diameter, and that is your answer

Answer 20

Thanks, you've just helped me a lot. :D