A ladder is placed against a building If the ladder makes a

A ladder is placed against a building. If the ladder makes a 55° angle with the ground, what is the measure of the angle that the ladder makes with the building?

A. 35°

B. 40°

C. 55°

D. 90°

Solution

A. In this problem, you know two of the three angles, one measuring 55° and the other measuring 90°.

Together those two angles measure 145°.

Since a triangle has a total of 180°, the third angle must measure 180° – 145° = 35°.