SSC CGL 2025 PYQ — Question 58

SSC CGL - 15 Sep 2025 - Shift 1 • Quantitative Aptitude • Q58

A circular disc of radius 9 cm is inscribed inside an equilateral triangle. What is the approximate area of the remaining portion of the triangle?

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e. 166 cm2.

For an equilateral triangle, inradius r = a36a\sqrt{3} \over 6

⇒ a = 6r36r \over \sqrt{3}

⇒ a = 18318 \sqrt{3}

Now, area of equilateral triangle = 34a2\frac{\sqrt{3}}{4} a^2

⇒ 34×(183)2\frac{\sqrt{3}}{4} \times (18 \sqrt{3})^2

⇒ 34×(324×3)\frac{\sqrt{3}}{4} \times (324\times3) = 2433243\sqrt{3}

Area of circle = πr2\pi r^2

⇒ π×92\pi \times 9^2 = 81π81\pi

Remaining area = 2433243\sqrt{3} - 81π81\pi

⇒ 420.88 - 254.58 = 166.30 ≈ 166