Question

Let ∠1, ∠2, and ∠3 have the following relationships.

Answer 1

Answer:

180°

Step-by-step explanation:

Vertical angles are opposite angles that share only a vertex.  Since ∠3 is adjacent to both ∠1 and ∠2, this means that ∠3 shares a side and vertex with both of these angles.

This means that ∠3 and ∠1 form a straight line; this makes them a linear pair, which makes their sum 180°.

Answer 2

3 can be anything greater than (but not equal to) 90 and 1 can be anything less than (but not equal to) 90 as long as angle 3 + angle 1 = 180 degrees.