Question

An isosceles triangle in which the two equal sides, labeled a, are longer than the base, labeled b.

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?

Answer 1

2(6.3)+b = 15.7 or 12.6+b = 15.7

Explanation:

Answer 2

The side labeled "a" is made the longer side. These are the two congruent sides. So a > b.

We are told that the longer side is 6.3, so a = 6.3, meaning that

2a+b = 15.7

2(6.3)+b = 15.7

12.6+b = 15.7

b = 15.7-12.6

b = 3.1

The triangle has sides of: 6.3, 6.3, 3.1

The perimeter is 6.3+6.3+3.1 = 15.7

Going back to the question "which equation can be used to find the length of the base?", it sounds like either you were given a list of multiple choice answers, or you just fill in the blank. If multiple choice, then try to see which answer matches with what I wrote above. If fill in the blank, then I would just enter either 2(6.3)+b = 15.7 or 12.6+b = 15.7