Question

A 6 inch personal pizza has 640 calories, with 240 of those from fat. A 12 inch pizza is cutinto 8 slices. Estimate the number of calories in one slice of a 12 inch pizza. Must use Pi*r2 proportions to solve.

Answer 1

Given:

Number calories in a 6-inch pizza = 640 calories

For the pizza of 6 inch

`A=\pi(3)^2=9\pi`

For the pizza of 12 inch

`A=\pi(6)^2=36\pi`

Number calories in a 6-inch pizza = 640 calories, therefore:

`\frac{A_{6\text{ inch}}}{A_{12\text{ inch}}}=(640)/(x)`

Substitute:

`\begin{gathered} (9\pi)/(36\pi)=(640)/(x) \\ Simplify \\ (1)/(4)=(640)/(x) \end{gathered}`

And solve for x:

`\begin{gathered} 1\cdot x=4\cdot640 \\ x=2560 \end{gathered}`

Now, Estimate the number of calories in one slice of a 12 inch pizza:

`(2560)/(8)=320`

Answer: 320 calories