Chapter 11.6, Problem 4PSA

To determine

To calculate:Thearea of circle whose circumference is $18\pi dm$ .

Answer to Problem 4PSA

The area of circle is $81\pi d{m}^2$ .

Explanation of Solution

Given information:

  $Circumferenceofacircle=18\pi dm$

Formula used:

Circumference of a circle: $C=2\pi r=\pi d$

r = radius of a circle.

d = diameter of a circle.

Area of a circle: $A=\pi r^2$

r = radius of a circle.

Calculation:

  

  $\begin{array}{l}C=\pi d\\ 18\pi =\pi d\\ d=18\\ r=\frac{d}{2}=\frac{18}{2}=9\end{array}$

  $\begin{array}{l}A=\pi r^2\\ $ =\pi {(9)}^2$=81\pi d{m}^2\end{array}$