The perimeter of the scalene triangle is 54.6 cm. A scalene triangle where all sides are different lengths. The base of the triangle, labeled 3 a, is three times that of the shortest side, a. The other side is labeled b. Which equation can be used to find the value of b if side a measures 8.7 cm? 8.7 plus b equals 54.6 17.4 plus b equals 54.6 26.1 plus b equals 54.6 34.8 plus b equals 54.6