Question

Question 37

The area of a semi-circle of radius 4r is

(a) $8\pi r^2$
(b) $4\pi r^2$
(c) $12\pi r^2$
(d) $2\pi r^2$

Answer 1

Given, radius of semi-circle = 4r
$\because$ Area of semi-circle $=\frac{1}{2}\times \pi \times radiu{s}^2$
$=\frac{1}{2}\times \pi (4r{)}^2=\frac{16}{2}\pi r^2=8\pi r^2$