Alternate interior angles add to 180°.

(3x + 17) + (x + 53) = 180

4x + 70 = 180

4x = 110

3(27 1/2) + 17 =

(27 1/2) + 53 =

(3x + 17) + (x + 53) = 180

4x + 70 = 180

4x = 110

**x = 27 1/2**One angle is3(27 1/2) + 17 =

**99 1/2 degrees**The other angle is(27 1/2) + 53 =

**80 1/2 degrees**