One side of the rectangle is 21 cm and the adjacent side is 9 cm longer. Calculate the perimeter and area of the rectangle.

Find the adjacent side of the rectangle if it is 9 cm longer than the side equal to 21 cm:

21 + 9 = 30 (cm).

We calculate the perimeter of the rectangle, equal to the doubled sum of its two sides:

P = 2 (21 + 30) = 2 * 51 = 102 (cm).

Find the area of a rectangle by the product of its two known sides:

S = 21 * 30 = 630 (cm²).

Answer: the perimeter of the rectangle is 102 cm, the area of the rectangle is 630 cm².