SSC CGL 2022 PYQ — Question 75

SSC CGL - 02 Dec 2022 - Shift 1 • Quantitative Aptitude • Q75

In the given figure, a circle is inscribed in △PQR, such that it touches the sides PQ, QR, and RP at points D, E, and F respectively. If the lengths of the sides PQ = 15 cm, QR = 11 cm, and RP = 13 cm, then find the length of PD. 

Show answer & explanation

Correct answer: D

Explanation

The correct answer is option 4 i.e. 8.5 cm.

The lengths of tangents drawn from an external point to a circle are equal

Let the value of ER = x

Hence using the concept given;

⇒ ER = FR = x

⇒ PF = 13 - x and PD = 13 - x (PF = PD)

⇒ QE = 11 - x and QD = 11 - x (QE = QD)

Now, QP = PD + QD

⇒ 15 = 13 - x + 11 - x

⇒ 2x = 24 - 15

⇒ x = 4.5

We know that, PD = 13 - x = 13 - 4.5 = 8.5 cm