Let's call the missing angles Q, R, and S. We know that Q = 2R and S = R - 8 and we also know that Q + R + S = 180. So that really just means that 180 = 4R - 8 Add 8 on both sides of the equal sign 188 = 4R So we divide on both sides of the equal sign by 4 47 = R And that means that Q = 2 * 47 So Q = 94 and S = 47 - 8 So S = 39 39 + 94 + 47 = 180 The missing angles are 39 degrees 94 degrees and 47 degrees.