Explanation-you would take 20+90 then subtract that from 180 which gives you 70 and 7x10 is equal to 70. 70+110=180. If x=10 then 5x would give you 50, then you add 20 and get 70. Then you add another 70 because the angle between the green line and black line is equal to 7x. This would give you 140. So 2y would have to be 2(20) which give you the remaining 40.
