Answer:
Explanation:
Note that the base of the building forms a right angle with the ground and the ladder forms a right triangle with the building.
On this case, we can apply Pythagorean theorem.
Since the ladder serves as the hypotenuse and the distance from the base of the building to the foot of the ladder is adjacent with the angle of elevation, we can use cosine.
Let A be the angle of elevation
cos A = adjacent/hypotenuse
cos A = 10ft/20ft
cos A = 0.50
A = Arc cos 0.50
A = 60°
With the given data, the angle of elevation turns out to be 60°. As it's beyond the allowable values, it won't satisfy the safety specifications of 35°-45°. The placement of the ladder is too steep and would need to be adjusted.