The area of a square is twice the area of a rectangle. The width of the rectangle is 3 feet shorter and the lenght is 4 feet longer than the side of the square. Find the side of the square?

Solution:

The side of square is X.

The area of square is X^2.

The area of rectangle = (x-3)(x+4)

So the equation is

x^2 = 2*(x-3)(x+4)

We solve it

x = 4

So the side of square is 4.