The ladder is making a right triangle so just use sin, cos, and tan to find either of the unknown angles.
(a) Using sin, you can find the missing angle and come up with the equation sinø = 9.2/10
ø=80 degrees
(b) Using a different triangle where the height of the building is unknown but all the angles are known. You can use cos to find the length of the base of the triangle.
cos75=x/10
x=9.2 ft
