The perimeter of the rectangle is 64 cm. The width is 12 cm. Calculate the area of the rectangle.

Condition:

P – 64 cm,

b = 12 cm,

a =? cm,

S -? cm².

Decision:

The perimeter of a rectangle is equal to the doubled sum of its 2 sides: P = 2 (a + b).

a = (P – 2 b): 2;

a = (64 – 2 * 12): 2 = (64 – 24): 2 = 40: 2 = 20 (cm).

The area of a rectangle is equal to the product of its sides: S = ab.

S = 20 * 12 = 240 (cm²)

Answer: 240 cm² area of a rectangle.