The width of the rectangle is 20% of its perimeter, and the length is 1.5 cm. Find the area of the rectangle.

Since the opposite sides of a rectangle are equal, therefore, its 2 lengths together are 3 cm, which is 60% of the perimeter. Let’s find how many cm two widths of such a figure, making up the proportion:

60% = 3 cm.

40% = x.

Let’s write the equation, acting according to the “cross” rule and find the value of the variable:

x = 3 * 40: 60 = 120: 60 = 2 cm.

2: 2 = 1 cm – width.

Let’s find the sum of all sides, through the formula:

P = 2a + 2b = 2 * 1.5 + 2 * 1 = 5 cm.

The area corresponds to:

S = a * b = 1.5 * 1 = 1.5 cm².