The width of the rectangle is 2 times less than the length. Find the area of the rectangle if the perimeter is 120 cm.

Solution:
Let x cm be the width of the rectangle, then 2x cm is the length of the rectangle. Since the perimeter is 120 cm, we make the equation:
120 = (2x + x) * 2;
120 = 3x * 2;
120 = 6x;
x = 120: 6;
x = 20 (cm) – the width of the rectangle;
2) 2x = 20 * 2 = 40 (cm) – the length of the rectangle;
3) S = a * b = 20 * 40 = 800 (cm ^ 2) – the area of the rectangle;
Answer: 800 cm ^ 2 is the area of a rectangle.
Explanations. Since the width of the rectangle is 2 times less than the length, then the length is twice the width, which means it is convenient to take x for the width, and 2x for the length.