Answer
Side-length of square = 22.5 units
Side-length of equilateral triangle = 30 units
Work Step by Step
Let side-length of square = x
Let side-length of triangle = y
y = 2x – 15
Perimeter of square = 4x
Perimeter of triangle = 3y = 3(2x – 15)
3(2x – 15) = 4x
6x – 45 = 4x
2x = 45
x = 22.5 units
y = 2(22.5) – 15 = 30 units
