Two right triangles with interior and exterior angles labeled. The first triangle has acute angles labeled 40 degrees and angle 1. The exterior angle opposite the right angle and angle 1 is labeled as angle 8. The second triangle has acute angles labeled as angle 3 and angle 5. The exterior angle opposite the right angle and angle 3 is labeled as angle 6. The exterior angle opposite angles 3 and 5 is labeled as angle 7. Angle 1 in the first triangle and angle 3 in the second triangle are vertical angles. Angle 2 forms a linear pair with angle 1 and with angle 3. Angle 4 forms a linear pair with angle 1 and with angle 3.