Answer:
x=4 degrees
Explanation:
its an equilateral triangle so all sides are equal, if one angle is 10x+20,then the rest are each 10x+20.This is a triangle and it adds up to 180 degrees. So in total, (10x+20)×3=30x+60.So you do this, 30x +60=180 degrees, you take the sixty to the other side and subtract it from 180 ,you'll get 120 degrees, then divide 120by 30x