Find 𝑟(36𝜋) and interpret its meaning.

Question

The circumference 𝐶 of a circle is a function of its radius given by 𝐶(𝑟) =2𝜋𝑟. Express the radius of a circle as a function of its circumference. Call this function 𝑟(𝐶). Find 𝑟(36𝜋) and interpret its meaning.

Answer 1

C = 2pi(r)

r (C) = C/2pi = 2pi(r)/2pi = r

r(36pi) = 36pi/2pi = 18

if the circumference = 36pi then the radius = 18