Question

Find the area of the shaded region in the figure below if the radius of the outer circle is eight and the radius of the inner circle is to keep your answer in terms of pi

Answer 1

From the given picture we can see 2 concentric circles, The big circle has a radius of 8 units and the small circle has a radius of 2 units

To find the area of the shaded, subtract the area of the small circle from the area of the big circle

`A_(sh)=A_b-A_s`

Since the area of the circle is

`A=\pi r^2`

Since

`r_b=8,r_(s=2)`

Substitute them in the rule above

`\begin{gathered} A_(sh)=\pi(8)^2-\pi(2)^2 \\ A_(sh)=64\pi-4\pi \\ A_(sh)=60\pi \end{gathered}`

The area of the shaded is 60pi square units