The perimeter of an equilateral triangle is 6 cm more than the perimeter of a square. the length of a side of the square is 3 cm less than the length of a side of the equilateral triangle. find the area of the square.

3t=4s+5          (s=side of square, t= side of triangle)

s=t-3, t=s+3, using this value for t in the first equation gives us:

3(s+3)=4s+5

3s+9=4s+5

-s=-4

s=4

so the side length of the square is 4cm and the area of a square is just s^2

A=16cm^2