Question

which angles are supplementary to each other? ∠13 and ∠9 ∠10 and ∠1 ∠15 and ∠9 ∠16 and ∠15

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: Analyze each option

• For ∠13 and ∠9: They are not adjacent and do not form a straight - line, so they are not supplementary.
• For ∠10 and ∠1: They are not adjacent and do not form a straight - line, so they are not supplementary.
• For ∠15 and ∠9: These two angles are adjacent and together they form a straight - line. So, ∠15+∠9 = 180 degrees, and they are supplementary.
• For ∠16 and ∠15: They are adjacent but form a right - angle (not a straight - line), so they are not supplementary.

Answer:

∠15 and ∠9