The perimeter of a rectangle is $40,$ and the length of one of its diagonals is $10 \sqrt{2}.$ Find the area of the rectangle.
A = 100 units2
Perimeter 40 and diagonal 10 • sqrt(2) indicate that this
figure is the special case of rectangle, which is a square.
Each side is 10, therefore the area is 10 • 10 = 100.
+1557 
