Question

Question #31fcf

Answer 1

The circumference of a circle with a diameter of exactly `9pi`cm or approximately `28.26`cm.

Explanation:

The number Pi (`pi`) is known as the ratio between the circumference and the diameter of any circle.

Where `C` is the circumference of the circle and `d` is the diameter:

`pi = C/d`

We may rearrange this to isolate our desired dimension (circumference).

Multiply by `d` on both sides.

`pid = C`

OR

`C = pid`

Now, use your known diameter with this formula.

`C = pi * 9`

The circumference is exactly `9pi` cm or approximately `28.26` using cm `pi ~~ 3.14`.