2018 · Q93
In the figuregiven below, ABCD is the diameter of a circle of radius 9 cm. The lengths AB, BC and CD are equal. Semicircles are drawn on AB and BD as diameters as shown in the figure. What is the area of the shaded region ?
Elementary MathematicsCircles
- A9π
- B27π
- C36π
- D81π
Explanation
AD = 18 (radius 9), AB = 6 (radius 3), BD = 12 (radius 6). Shaded area = semicircle on AD - semicircle on BD + semicircle on AB = (pi/2)(81 - 36 + 9) = 27 pi. Hence option B.