Answer: 130
In order to solve for <4, you need to know that supplementary angles add up to 180°.
<3 = 50
180 - 50
130
**For future questions**
1. The sum of the interior angles of a triangle is 180°
2. Alternate interior angles are congruent
3. The exterior angle of a triangle is the sum of the nonadjacent interior angles
See attachment below.
