
Jungseub R. answered 03/30/23
A Licensed Math Teacher with Fourteen Years of Tutoring Experience
Vertical angles are the opposite angles formed by two intersecting lines,
and they are always equal in measurement.
Thus, the vertical angles, <1 and <2, are congruent. (<1 ≅ <2)
Complementary angles are angles that add up to 90º.
Thus, <2 + <3 = 90º.
Since <1 = 71° and <1 = <2, <2 is also 71°.
Substitute <2 with 71° in the equation <2 + <3 = 90º:
71° + <3 = 90°
Subtract 71° from both sides of the above equation:
<3 = 90° - 71° = 19°
Therefore, the measurement of <3 is 19°.