Question

For safety reasons, the manufacturer of a ladder recommends that it be used in such a way that the base of the ladder is no farther than 91 cm from the base of the wall it is leaning against. If the ladder is 350 cm long, What angle does the ladder make with the ground?

Answer 1

See attached picture for better understanding of the problem. In the problem, the given values are the following:
hypotenuse = length of the ladder
adjacent = base of the ladder to base of the wall
Solving the angle x, we have the solution as below: 
cos x = adjacent / hypotenuse
cos x = 91 / 350
x = 74.93°

The answer is 74.93°.