Chapter 11.4, Problem 47SPR

To determine

To find: The area of the circle whose radius is $9\text{cm}$ .

Answer to Problem 47SPR

The area of the circle is $490.9{\text{mm}}^2$ .

Explanation of Solution

Given:

The diameter is $25\text{mm}$ .

Calculation:

Consider the area of the circle is of the form,

  $A=\pi {\left(\frac{d}{2}\right)}^2$

Here, $d$ is the diameter.

Then,

  $\begin{array}{c}A=\pi {\left(\frac{25\text{mm}}{2}\right)}^2\\ =156.25\pi {\text{mm}}^2\\ =490.9{\text{mm}}^2\end{array}$