Chapter 11.6, Problem 3PSA

To determine

To calculate: The circumference of circle.

Answer to Problem 3PSA

Circumference of circle is $62.85$ cm.

Explanation of Solution

Given information :

Area of circle is $100\pi$ ${\text{cm}}^2$

Formula used: Circumference of circle = $2\pi r$

Area of circle = $\pi r^2$

Calculation: As, Area of circle = $100\pi$ ,

  $\begin{array}{l}\Rightarrow \pi r^2=100\pi \\ \Rightarrow r^2=\frac{100\pi }{\pi }\\ \Rightarrow r^2=100\\ \Rightarrow r=\sqrt{100}\\ \Rightarrow r=10\text{ cm}\end{array}$

Now, Circumference of circle = $2\pi r$

  $\begin{array}{l}\Rightarrow 2\times \frac{22}{7}\times 10\\ \Rightarrow \frac{440}{7}\\ \Rightarrow 62.85\text{ cm}\end{array}$