A22 foot ladder is placed against a vertical wall of a building with the bottom of the ladder standing on level ground 16 feet from the base of the building. how high up the wall does the ladder reach

You need to work this out using pythagoras' theorem.

Csquared=Asquared+Bsquared

But you are finding out A, not C, so you must rearrange the equation.

Asquared=Csquared-Bsquared
Asquared= 484-256
Asquared=228
A=Square root of 228
A=15 :) 

The correct answer to your questin is 38

The answer is 76° i believe