Since the triangle is equilateral, QR = RS = QS. a. MS = (1/2)74 MS = 37 b. Half of the equilateral triangle makes a right triangle. Use Pythagorean Theorem to find QM. a^2 + b^2 = c^2 37^2 + b^2 = 74^2 1369 + b^2 = 5476 subtract 1369 from both sides b^2 = 4107 take the square root if both sides b = 64.1 QM = 64.1
