For any inscribed quadrilateral, the opposite angles add to 180
(angle PMN) + (angle NOP) = 180
(8x-24) + (4x) = 180
12x-24 = 180
12x-24+24 = 180+24 ..... add 24 to both sides
12x = 204
12x/12 = 204/12 ..... divide both sides by 12
x = 17
angle NOP = 4x
angle NOP = 4*17
angle NOP = 68 degrees
