Question

The area ofthe shaded portion in the given figure is

• A. 7.5 $\pi$ sq. units
• B. 6.5 $\pi$ sq. units
• C. 5.5 $\pi$ sq. units
• D. 4.5 $\pi$ sq. units

Answer 1

The correct option is D 4.5 $\pi$ sq. units

Given that:

Radius of bigger semi circle $R=5$ units

Area of Bigger semi circle $A=\frac{\pi }{2}{R}^2\Rightarrow 12.5\pi$ unit

Radius of smaller semi circle $r=5-1\Rightarrow 4$ units

Area of Bigger semi circle $a=\frac{\pi }{2}{r}^2\Rightarrow 8\pi$ unit

Hence,

Area of shaded portion $=A-a\Rightarrow 12.5\pi -8\pi \Rightarrow 4.5\pi$ unit${}^2$