JAMB Mathematics 1979 Question 22

Question 22

Trigonometry

A ladder resting on a vertical wall makes an angle whose tangent is 2.4 with the ground. If the distance between the foot of the ladder and the wall is 50cm, what is the length of the ladder?

A.1m
B.1.1m
C.1.2m
D..9m
E.1.3m.

Show the answer and explanation

Answer: E (1.3m.)

Explanation

tan θ = 2.4 = 12/5 means a 5-12-13 triangle, so cos θ = 5/13. Ladder = 50 ÷ (5/13) = 130cm = 1.3m.