Then: x+y=5 ①
X 2 +y 2 = 13 ②
From ①: x 2 +2xy+y 2 =25 ③
③-① Get: 2xy= 12?
∫ The sum of the areas of four right triangles is 2xy.
∴ The area of Little Square = 13- 12 = 1
A: The area of a small square is1;
(2) as shown in figure