An isosceles triangle has two equal angles. if the measure of the third angle is 40 degrees less than the sum of the two equal angles, find the measures of the three angles.

So let's call the missing angles A, B, and C. We know that A + B + C = 180 and we also know that A = B and that C = A + B - 40. So our equation looks like this
180 = 4A - 40 and we add 40 on both sides of the equal sign and get
220 = 4A and we divide on both sides of the equal sign by 4 to get 
55 = A So that means B = 55 as well. That means 55 + 55 = 110 and 110 - 40 = 70 So C = 70 and to check, 55 + 55 + 70 = 180.
The measures of the three angles are; 55 degrees, 55 degrees, and 70 degrees.