Find the perimeter of a rectangle if its perimeter is 30 and the aspect ratio is 1: 2.

It is known from the condition that the perimeter of the rectangle is 30, and the sides are in 1: 2 ratio.

In order to find the area of a rectangle, we need to know the sides of the rectangle.

Let’s introduce the coefficient of similarity x and compose and solve a linear equation with one variable.

The sides of a rectangle can be written as x and 2x.

We find the perimeter of the rectangle by the formula:

P = 2 (a + b);

2 (x + 2x) = 30;

x + 2x = 15;

3x = 15;

x = 5.

One side is 5 and the other is 10.

The area of the rectangle is:

S = a * b = 5 * 10 = 50 sq. units.