Find the perimeter of a rectangle if its area is 18 and the ratio of adjacent sides is 1: 2.

From the condition it is known that the area of the rectangle is 18, and the ratio of adjacent sides is 1: 2. And we need to find the perimeter of the rectangle.

To find the perimeter, we apply the formula:

P = 2 (a + b).

To calculate the sides of a rectangle, we will compose and solve an equation using the formula for finding the area of a rectangle:

S = a * b.

We write the sides of the rectangle as k and 2k and get the equation:

k * 2k = 18;

2k ^ 2 = 18;

k ^ 2 = 9;

k = 9 cm length of the smaller side and 9 * 2 = 18 cm length of the larger one.

P = 2 (9 + 18) = 2 * 27 = 54 cm.