GATE 2021 BM – Question 9
PQRS is a square. The shaded region is the intersection of two circular sectors, each of radius equal to the square’s side, with centres at S and Q. What is the probability that a uniformly chosen point in the square lies in the shaded region?

Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: (C) $\pi/2-1$
Explanation
Let side length be r. The two quarter-disc sectors each have area πr²/4, and their union fills the square. By inclusion–exclusion, intersection area=πr²/2−r². Dividing by square area r² gives π/2−1, C. The radius cancels.
More Spatial Aptitude: Spatial Reasoning and Visualization questions
- GATE 2026 CS (CS1) Q2
- GATE 2026 CS (CS1) Q7
- GATE 2026 CS (CS2) Q2
- GATE 2026 CS (CS2) Q7
- GATE 2026 CS (CS2) Q9
- GATE 2025 CS (CS2) Q4
All Spatial Aptitude: Spatial Reasoning and Visualization questions →