Question

A fire department's ladder is 110 feet long. A firefighter is trying to reach the top of a 100 foot building by leaning the ladder against the building. What is the angle of elevation for the rescue ladder?

Answer 1

sin-¹(10/11)

Explanation:

The height of the building is 100 ft and the ladder is 110ft long .We can imagine this situation as a right angled ∆. For figure refer to the attachment .

• We can use ratio sine here. Let the angle of elevation be theta.

In ∆ ABC :-

=> sinθ = p/h

=> sinθ = 100ft / 110 ft

=> sinθ = 10/11

=> θ = sin -¹ ( 10/11) .

Hence the angle of elevation is sin -¹ ( 10/11).