Question

A sheet of paper is in the form of a rectangle ABCD in which AB = 40 cm and AD = 28 cm. A semi-circular portion with BC as diameter is cut off. Find the area of the remaining paper.

Answer 1

Area of rectangle = length × breadth 

Area of rectangle = 40 × 28 

Area of rectangle = 1120 cm² 

Diameter of semi circular portion = 28 cm 

Radius of semi circular portion = \(\frac{28}2\) = 14 cm 

So, 

Area of semi circular portion = \(\frac{πr^2}2\)

= \(\frac{22\times14\times14}{7\times2}\) = 308 cm²

Area of remaining portion = 1120 – 308 = 812cm²