SSC CHSL 2020 PYQ — Question 71

SSC CHSL - 20th October 2020 - Shift 1 • Quantitative Aptitude • Q71

A is a point at a distance 26 cm from the centre O of a circle of radius 10 cm. AP and AQ are the tangents to the circle at the point of contracts P and Q. If a tangent BC is drawn at a point R lying on the minor arc PQ to intersect AP at B and AQ at C, then the perimeter of ΔABC is:

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e 48 cm

Understanding Application

The length of tangents drawn from an external point to a circle is equal.

The Pythagoras theorem states that the sum of squares of perpendicular and base of the right-angle triangle is equal to the square of the hypotenuse.

⇒ BP = BR and CR = CQ

Perimeter of ∆ABC = AB + BR + RC +AC

⇒ AB + BP + QC + CA

We know that AP = QA

⇒ AP + QA = 2AP

⇒ AO2 = AP2 + PO2

⇒ AP = √(676 - 100)

⇒ 24 cm

Perimeter of ABC  = 2AP

⇒ 2 × 24 = 48 cm