Question

Ellen has two pizzas left after a party. One iswhole and one has been half-eaten. Thewhole pizza has a radius of 7 inches. The halfeaten pizza has a diameter of 20 inches.Which pizza has a greater circumference?

Answer 1

Whole Pizza

Circular shape with radius 7 inches

We need to find the circumference. Let's use the formula and find the circumference:

`\begin{gathered} C=2\pi r \\ C=2\pi(7) \\ C=14\pi \end{gathered}`

Half Eaten Pizza

Has radius 20 inches.

We will use the formula for the circumference of a circle and halve it to find circumference of half circle.

Shown below:

`\begin{gathered} C=(2\pi r)/(2) \\ C=\pi r \\ C=20\pi \end{gathered}`

The second pizza (half eaten pizza) has a greater circumference.