From a rectangular sheet of paper ABCD wit AB = cm and AD = 28 cm, a semicircular portion wit BC as diameter is cut off. Find the area of the remaining paper.
Given:
Length of rectangular sheet of paper = 40 cm
Breadth of rectangular sheet of paper = 28 cm
Radius of the semicircular cut out = 14 cm
∵ Area of rectangle = length × breadth
∴ Area of rectangular sheet of paper = 40 × 28
= 1120 cm2
∵ Area of semicircle = πr2
∴ Area of semicircular cut out = ×
× 14 × 14
= 22 × 14 = 308 cm2
Thus, the area of remaining sheet of paper = Area of rectangular sheet of paper – Area of semicircular cut out
= 1120 – 308 = 812 cm2
Hence, the area of remaining sheet of paper is 812 cm2.