Answer:
The height of the building is: 20.2 foot
Explanation:
Using the Pythagorean theorem we can find another side of a right-angled triangle if two among three sides are given.

where a, and b are sides and c is the hypotenuse.
In our case base (b) is given and ladder length (c) is given, so the height of building (a) is :



So the rounded answer of height is: 20.2 foot