Chapter 12.2, Problem 7GP

To determine

To find : The area of the doughnut.

Answer to Problem 7GP

  $86.35c{m}^2$

Explanation of Solution

Given information :

The given information is, $d_1=8$ centimeters and $d_2=3$ cm, where $d_1$ and $d_2$ are diameters respectively.

Formula Used:

Area of circle = $2\pi r^2$

Calculation :

Here, $r_1=\frac{8}{2}=4$ cm and $r_2=\frac{3}{2}$ cm

Area of top of doughnut $=2\pi \left(r_1^2-r_2^2\right)$

  $\begin{array}{l}=2\times (3.14)\times (16-2.25)\\ =2\times (3.14)\times (13.75)\\ =86.35{\text{cm}}^2\end{array}$