Exterior angle theorem
16x - 7 = 8x + 2 + 10x - 19 ===> 16x -7 = 18x - 17
16x - 16x - 7 = 18x - 16x - 17 ===> -7 = 2x - 17
-7 + 17 = 2x - 17 + 17 ===> 10 = 2x ======> 5 = x
Plug x in to each equation.
Angle P: 8(5) + 2 = 42 deg, Angle Q: 10(5) - 19 = 31
The sum of interior angles = 180. 180 - 42 -31 = 107 deg (angle of PRQ)
To check that line other angle : 16(5) -7 = 73 deg + 107 = 180 deg