The perimeter of the rectangle is 28 cm. The length is 12 cm. Find the area of the rectangle.

The opposite sides of a rectangle are equal, therefore, the sum of its sides (perimeter) is calculated by the formula:

P = 2a + 2b. Find the unknown side, provided that its value = 28 cm and length = 12 cm:

12 * 2 + 2b = 28,

24 + 2b = 28. We leave the unknown on the left side of the equation, and transfer the number to the right, changing the sign in front of it to the opposite:

2b = 28 – 24 = 4. To find the second factor, divide the product by the first:

b = 4: 2 = 2 cm.

The area of a rectangle is determined by the formula:

S = a * b = 12 * 2 = 24 cm².