Question

A ladder leaning against a house makes an angle of 65 degrees with the ground. The foot of the ladder is 7 feet from the foot of the house. How long is the ladder? Round to the nearest tenth.

Answer 1

You must learn the trig relationships of a right-angled triangle!

In this case:
cos65° = 7/h
h = 7/cos65° = appr 16.6 m

or sec 65 = h/7
h = 7sec 65 = 7(2.36620...) = 16.6 m