Question

which angle is complementary to ∠adb?

Explanation:

Step1: Recall complementary - angle definition

Two angles are complementary if their sum is 90 degrees. Assuming that ∠ADC is a right - angle (90 degrees) and ∠ADC=∠ADB + ∠BDC.

Step2: Identify the complementary angle

Since ∠ADB+∠BDC = 90 degrees, the angle complementary to ∠ADB is ∠BDC.

Answer:

∠BDC