O is the center of a circle with AC = 24 cm, AB = 7 cm, ∠BOD = 90°. The area of shaded region is:

Answer & explanation
Correct answer: option 3

Area of shaded region I = Area of semi circle - Area of Δ ABC
BC2 = AC2 + AB2 = 72 + 242 = 25 c.m.
⇒ Area of region I = \(\frac{1}{2}\)\(\pi \)r2 - \(\frac{1}{2}\) AC × AB
= \(\frac{22}{7}\) × \(\frac{1}{2}\) × \(\frac{25}{2}\) × \(\frac{25}{2}\) - \(\frac{1}{2}\) × 24 × 7
= 245.53 - 84 = 161.535
⇒ Area of region II = area of quadrant BOD = \(\frac{1}{4}\) \(\pi \)r2
= \(\frac{1}{4}\) × \(\frac{22}{7}\) × \(\frac{25}{2}\) × \(\frac{25}{2}\) = 122.76
Total area = 161.535 + 122.76 = 284.295 cm2