In the figure given below, ABC is a right-angled triangle where ∠ A = 90°, AB = p cm and AC = q cm. On the three sides as diameters semicircles are drawn as shown in the figure. The area of the shaded portion, in square cm, is
In the figure given below, ABC is a right-angled triangle where ∠ A = 90°, AB = p cm and AC = q cm. On the three sides as diameters semicircles are drawn as shown in the figure. The area of the shaded portion, in square cm, is Correct Answer pq/2
Given, AB = p cm and AC = q cm
∵ Area of right-angled triangle = 1/2 × Base × Height
⇒ Area of triangle ABC = pq/2
Applying Pythagoras theorem in ∆ABC,
⇒ BC2 = AB2 + AC2
⇒ BC2 = (p2 + q2)
∵ Area of semi-circle = (π/8) × (diameter)2
⇒ Area of semi-circle with diameter AB = (π/8) × (p)2 = πp2/8 cm2
⇒ Area of semi-circle with diameter AC = (π/8) × (q)2 = πq2/8 cm2
⇒ Area of semi-circle with diameter BC = (π/8) × (p2 + q2) = π(p2 + q2) /8 cm2
∴ Area of shaded region = (pq/2) + (πp2/8) + (πq2/8) – = (pq/2) cm2
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Feb 20, 2025