SSC CGL 2021 PYQ — Question 69

The correct answer is option 3 i.e. $\frac{2}{5}$

Given :

AB = 20 cm, BC =21 cm and AC = 29 cm

Formula used :

Pythagoras theorem,

(Hypotenuse)² = (Base)² + (Perpendicular)²           ----- (1)

Calculations :

Using equation (1)

⇒ 29² = 21² + 20² 

⇒ 841 = 441 + 400

⇒ 841 = 841

The triangle satisfies the pythagoras theorem therefore ABC is a right angled triangle

⇒ cot C = BC/AB = 21/20        ----- (1)

⇒ cosec C = AC/AB = 29/20          ----- (2)

⇒ tan A = BC/AB = 21/20         ----- (3)

Put the value of equation (1), (2) and (3) in the equation below

⇒ cot C + cosecC - 2tan A

⇒ 21/20 + 29/20 - 2(21/20)

⇒ (21 + 29 - 42)/(20)

⇒ 8/20

⇒ 2/5