Answer:
73°
Explanation:
This equation uses two supplementary angles. Supplementary angles are two angles that add up to 180 degrees.
The triangle has two angles implied, 30 degrees and (180-137) degrees.
(180 - 137) = 43 degrees
Now that we have two angles inside the triangle, we subtract them from 180 to find the last angle.
180 - 43 - 30 = 107
The angle with a measure of 107 degrees and angle 3 are supplementary
180 - 107 = 73 degrees