This isocles triangle has 2 sides of equal length, a that are longer than the length of the base, b, The perimeter of the triangle is 15.7 centimeters. The equation is 2a+b=15.7 models this information. If one of the longer sides is 6.3 centimeters which equation can be used to find the length of the base? A) 6.3+b=15.7 B) 12.6+b=15.7 C) 2a+6.3=15.7 D) 2a+12.6=15.7