One side of the rectangle = 40 cm. And its perimeter is 210 cm. Calculated the area of the rectangle.

If in a rectangle the length of one side is 40 cm, then the opposite side has the same length, that is, 40 cm, the total length of the sides is 80 cm, therefore the length of the other two sides in total will be 210 – 80 = 130 cm.,

130: 2 = 65 cm – the length of the other side of the rectangle.

Let’s find the area 40 * 65 = 2600 cm².

Answer: The area of the rectangle is 2600 cm².