Answer:
<1 ≅ <3 (congruence property)
Explanation:
Given that: <1 and <3 are vertical angles.
Prove: <1 congruent to <3
Vertical angles are angles that are vertically opposite, and are formed under the same conditions. Thus, they are always congruent.
<1 + <2 =
(sum of angles on a straight line)
Also,
<2 + <3 =
(sum of angles on a straight line)
So that,
<1 + <2 ≅ <2 + <3 =
Thus, we can say that;
<1 + <2 ≅ <2 + <3
Since <2 is a common angle on both sides, then;
<1 ≅ <3 (congruence property)