Question

A triangle has one side that measures 12, another side that measures x, and a third side that measures 4 less than x. The perimeter is 26.

Which equation would we use to find the value of x?

x + x + 4 + 12 = 26
x + x - 4 + 12 = 26
x + x - 4 = 26
x + x + 4 = 26

Answer 1

The equation for perimeter is as following...

Perimeter = ∑ side lengths (sum)

26 = 12 + x + x - 4

∴ our answer is x + x - 4 + 12 = 26