Firstly, let's solve for the third interior angle of the triangle. Interior angles of all triangles add to equal 180 degrees; to find the third interior angle, set the sum of the two known angle measures and the third angle measure, x, equal to 180 and solve.
180 = 75 + 50 + x 180 = 125 + x 55 = x
Now that we know all interior angle measures, we can begin to name the sides from shortest to longest.
The shortest side will always be opposite the smallest interior angle - in this case, angle H. This rule applies to both the other sides and angles; the longest side is opposite the largest interior angle, which in this case is angle G. (This means the second-largest angle is opposite the second-longest side - the sole remaining angle.)
The order of sides from shortest to longest: side IG, side GH, side HI.
