Question

In an equilateral triangle, all 3 sides are equal length, and the perimeter of an equilateral triangle is 3 times the length of one side.
If one side measures 12 + 4x, and the measure of another side is 5x + 14, what is the perimeter of the equilateral triangle?

Answer 1

Since all the sides are equal, let's set 12 + 4x equal to 5x + 14

12 + 4x = 5x + 14

Subtract 4x from both sides and subtract 14 from both sides.

-2 = x

Let's plug -2 in for x into one of the side measurements.

12 + 4(-2) = 12 + -8 = 4

The perimeter is equal to the measure of one side times 3

4*3 = 12

The perimeter of the equilateral triangle is 12.