QR is diameter of circle.
Therefore, ∠RPQ = 90° [Angle in semicircle is right angle]
In APQR, by Pythagoras theorem,
RP² + PQ² = RQ²
(7)² + (24)² = RQ²
⇒ RQ² = 576 + 49 = 625
⇒ RQ = √625 = 25
Therefore, the radius of circle = RQ/2 = 25/2 cm
Area of shaded region = Area of semicircle – Area of APQR
= 1/2 × πr² – 1/2 PR × PQ = 1/2 × π(25/2)² – 1/2 × 7 × 24 = 1/2 × 22/7 × 25/2 × 25/2 – 7 × 12
= 6875/28 – 84 = (6875 – 2352)/28 = 4523/28 cm²

Here is the video explanation ✌😇