Question

The circumference of a coin is 8π What is the radius? What is the diameter?

Answer 1

The constant π is defined as C/d, meaning pi is the constant when the circumference of a circle is divided by the diameter of that circle. Anyway:

πd=C divide both sides by π

d=C/π, if C=8π then

d=8π/π

d=8

So the diameter is 8 units.

Answer 2

Find the radius first.
Circumference of a circle:

`=2 \pi r`

`8 \pi =2 \pi r`
`(8 \pi )/(2 \pi ) = r`
r=4

diameter = radius x 2
4x2 = 8