First we add all the angles together
x + 2x - 20 + 2x + 10 = 5x - 10
Now, you should know that all the angles in a triangle add up to 180°
180 = 5x - 10
Move the 10 to the other side
190 = 5x
Divide both sides by 5
x = 38
So the angles sizes in ascending order are
38 , 46 , 86
