SSC CGL 2023 PYQ — Question 54

SSC CGL - 18 July 2023 - Shift 1 • Quantitative Aptitude • Q54

Two concentric circles of radii 15 cm and 13 cm are given. Find the length of the chord of the larger circle which touches the smaller circle.

Show answer & explanation

Correct answer: C

Explanation

The correct answer is Option 3 i.e.  414\sqrt{14}.

PQ touches the smaller circle and OM is perpendicular to QP which divides the PQ into two equal parts.

OM = 13 (radius of smaller circle)

OP = 15 (radius of bigger circle)

In right-angled OMP

⇒ (OP)2 = (OM)2 + (PM)2

⇒ 152 = 132 + (PM)2

⇒ (PM)2 = 225 - 169

⇒ PM2 = 56

⇒ PM = √56 = √7 × 2 × 2 × 2 = 2√14

Now,

⇒ PQ = 2 PM

⇒ PQ = 4√14 cm

The length of the chord which touches the smaller circle is 4√14 cm