Question

The plastic lid of a cylindrical container is a circle. The lid has a radius of 9centimeters. What is the circumference of the lid?

Answer 1

We are asked to determine the circumference of a 9 cm radius circle. To do that we will use the following formula:

$S=2\pi r$

Where:

$\begin{gathered} S=\text{ circumference} \\ r=\text{ radius} \end{gathered}$

Now, we substitute the value of the radius:

$S=2\pi(9cm)$

Solving the operations:

$S=18\pi=56.55cm$

Therefore, the circumference is 56.55 cm.