Equilateral triangle's angles are each 60 degrees and all sides are the same length.
How to find missing angles for triangles!
Triangle's degrees is 180.First add the angles that you have. Next subtract the number you got from the angles you added to 180 degrees and that's your missing angle.
How to find missing angles in quadriaterals!
All quadriateral's angles make 360 degrees. First add up all the angles you have. Then subtract that number from 360 degrees and thats your missing angle.