Mensuration (C10)

In the given figure, ABCD is a rectangle of dimensions 21 cm × 14 cm. A semicircle is drawn with BC as diameter. Find the area and the perimeter of the shaded region in the figure.

 

Solution

Area of shaded region = Area of rectangle - Area of semi-circle

= (21 × 14) – ½ × π × 7 × 7

= 294 – 77

= 217 cm2

Perimeter of shaded region = 21 + 14 + 21 + π × 7

= 56 + 22

= 78 cm