SSC CPO 2019 PYQ — Question 139

SSC CPO Tier I - 12th March 2019 - Shift 1 • Quantitative Aptitude • Q139

P is a point outside a circle and is 26 cm away from its center. A secant PAB drawn from P intersects the circle at points A and B such that PB = 32 cm and PA = 18 cm. The radius of the circle (in cm) is:

Show answer & explanation

Correct answer: B

Explanation

The correct answer is Option 2 i.e 10

Given PO = 26 cm , PB = 32 cm , PA = 18 cm

Let OC = r cm

So, PC = (26 - r) cm

We know that PA × PB = PC × PD

⇒ 18 × 32 = (26 - r) × (26 + r)

⇒ 18 × 32 = (26)2 - r2

⇒ 576 = 676 - r2

⇒ r2  = 100

⇒ r = 10 cm