Chapter A.8, Problem 54AYU

To determine

To find: What is its radius?

Answer to Problem 54AYU

Radius is 3.

Explanation of Solution

Given:

A 39-ounce can of Hills Bros. coffee requires $188.5$ square inches of aluminium. If its height is 7 inches.

Calculation:

$S=2\pi r^2+2\pi rh$

$S=2\pi \left(r^2+rh\right)=188.5$

$=\left(r^2+rh\right)=\frac{188.5}{2\pi }$

$=r^2+7r-30=0$

Therefore,

$\left(r+10\right)\left(r-3\right)=0$

$r=3$ inches is the radius.