Question

which angle is supplementary to ∠1?

Explanation:

Step1: Recall supplementary - angle definition

Two angles are supplementary if their sum is 180 degrees. Adjacent angles that form a straight - line are supplementary.

Step2: Identify adjacent angle to ∠1

∠1 and ∠4 form a straight - line. So, ∠1+∠4 = 180 degrees.

Answer:

∠4