What is the measure of angle NOP

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

-4x/5+8.8. I think that's it, and if it isn't, i don't know.