Question

An observer 2.25 m tall is 42.75 m away from a chimney. The angle of elevation of the top of the chimney from her eyes is 45${}^{\circ }$. What is the height of the chimney?

• A. 40 m
• B. 35 m
• C. 45 m
• D. 50 m

Answer 1

The correct option is C

45 m

BC is part of the chimney above the person's height

A is the head of the observer

It is given that AB is 42.75 m

Since it is an isosceles right-angled triangle

BC = 42.75 m

Hence, total height of the chimney = person's height + BC = 2.25 + 42.75 = 45m