Question

An equilateral triangle and a square have the same perimeter. One side of the triangle measures 28 units. What is the area of the square

Answer 1

The perimeter of a triangle assuming that all the sides are the same, would be 3 multiplied by 28 to get 84. Since the perimeter of the square is the same, that would mean that 84 units is the total addition of the 4 sides of the square. So divide 84 by 4 to get the length of one side ( which is 24 units). 
Finally, the area of a square is defined as two sides multiplied by each other, so 24 multiplied by 24. 
Hope this helps.