SSC CHSL 2023 PYQ — Question 68

SSC CHSL - 10 March 2023 - Shift 3 • Quantitative Aptitude • Q68

Three circles of radius 7 cm are placed in such a way that each circle touches the other two. What will be the area of the portion enclosed by these three circles?

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e. 493−77cm249\sqrt{3}-77cm^{2}.

Each side of equilateral triangle = r + r = 7 + 7 = 14 cm

Angle subtended by the sector in an equilateral triangle = 60°

Area of a sector of circle = (θ/360) × πr2 = (60/360) × (22/7) × 72 ⇒ 77/3 cm2

Area of equilateral triangle = (√3/4) × 142 = 49√3 cm2

Area enclosed between circles = Area of a triangle - 3 (Area of the sector)

= 49√3 - 3(77/3)

= 49√3 - 77 cm2

Hence, the area enclosed between the circles is 49√3 - 77 cm2.