This isosceles triangle has two 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 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?

Given that the length of the longer side is a=6.3 and that of that of the shortest side which is the base is b, with perimeter 2ab=15.7, to get the equation that will be used to solve for b, we make b the subject:
2ab=15.7
divide both sides of the equation by 2a
(2ab)/(2a)=15.7/(2a)
b=15.7/(2a)
therefore the equation that was used to solve for b will be:
b=(15.7)/(2a)
given that =6.3, the value of b will be:
b=15.7/(2×6.3)
  =15.7/12.6
  =1.2460 cm

The answer would be b

The answer would be the second choice : )