Answer:
30°
Step-by-step explanation:
The measure of angle the ladder makes with the wall = 180 - (the measure of angle the ladder makes with the ground + 90°)
Measure of angle the ladder makes with the ground = 180 - 120 = 60°
Therefore,
The measure of angle the ladder makes with the wall = 180 - (60 + 90°)
= 30°