posted by Renee .
The sides of a square are one-third as long as the sides of an equilateral triangle. The difference between their perimeters is 20 centimeters. How long is each side of the triangle? Define your variables.
let the sides of the square be x cm each.
let the sides of the equilateral be 3x each
3(3x) - 4x = 20
5x = 20
x = 4
so the square is 4 by 4
the triangle has sides 12 each.