33.0 ft ladder just reaches the top of a building & forms an angle of 45.5o with the wall of the building How many ft tall is the building?

Let h ft be the height of the building.

cos45.5° = h/33.0
h = 33.0 cos45.5°
h = 23.1

The building is 23.1 ft tall.

height = 33sin(45.5°)

use cosine

The ladder, building and ground make an right triangle with the ladder being the hypotenuse.
Since you want to find the Side adjacent(Building height) you need to use the cosine

cos(45.5) = Side Adjacent / Hypotenuse
So: Height = 33*cos(45.5)