Hi sri340,

if the rectangles must not be squares, then they may be aligned side by side within the square.

Then 2 sides of the rectangles equal the square's side lengths,

and the other 2 sides are one quarter of the length of the square's sides.

Since 4x is 144, x is a quarter of this.

hence you can find the rectangle's perimeter from this.

If the rectangles can be squares, then the side lengths are half the square's side lengths.