The perimeter of the rectangle is 36cm. The sum of the lengths of its three sides is 25cm. What is the area of this rectangle?

1. Find the length of one of the sides of the rectangle. To do this, subtract the length of three sides from the perimeter. 36 – 25 = 11 cm.
2. The sides of the rectangle are equal in pairs, so the third side will be equal to the first = 11 cm.
3. Find the lengths of the second and fourth sides. To do this, subtract the lengths of the known sides from the perimeter and divide by 2. (36 – 11 – 11) / 2 = 7 cm.
4. Find the area. 11 * 7 = 77 cm square.
Answer: 77 cm square.