Question

What is the area of a semi-circle with circumference $88cm$?

• A. $400$ sq cm
• B. $420$ sq cm
• C. $440$ sq cm
• D. $460$ sq cm

Answer 1

The correct option is D $460$ sq cm

Circumference of semi-circle$=88cm\pi r+2r=88cmr(\frac{22}{7}+2)=88r\left(\frac{36}{7}\right)=88r=\frac{88\times 7}{36}=\frac{154}{9}cm$
area of semi-circle$=\frac{1}{2}\pi r^2=\frac{1}{2}\times \frac{22}{7}\times \frac{154}{9}\times \frac{154}{9}\approx 460{cm}^2\left(approx\right).$