Question

The radius of a circle is 9. Using π, which equation expresses the ratio of the circumference of the circle to the circle's diameter?

Answer 1

`\large\boxed{(C)/(d)=\pi}`

Explanation:

We have the radius r = 9.

The formula of a circumference of a circle:

`C=2\pi r`

The diameter d = 2r.

The ratio of the circumference of the circle to the circle's diameter:

`(C)/(d)=(2\pi r)/(2r)=\pi`