Use four rectangles of the same size and a small square to make a large square with a side length of 13dm. What is the perimeter of each rectangle

Use four rectangles of the same size and a small square to make a large square with a side length of 13dm. What is the perimeter of each rectangle

As shown in the picture, the yellow part is a big square made up of four rectangles of the same size and a small square,
So if the length of the original rectangle is a and the width is B, then & nbsp; a + B = 13dm,
So perimeter = 2 * (a + b) = 26dm