The length of the rectangle is 3 times its width. By what percentage will the perimeter

| February 3, 2021 | education

The length of the rectangle is 3 times its width. By what percentage will the perimeter of the rectangle decrease by 20% and its width by 40%?

Let’s denote the width of this rectangle through x.

According to the condition of the problem, the length of this rectangle is 3 times its width, therefore, the length of this rectangle is 3x, and the perimeter P of this rectangle is:

P = 2 * (3x + x) = 2 * 4x = 8x.

If its given rectangle is reduced by 20%, and the width by 40%, then the length of the resulting rectangle will be 0.8 * 3x = 2.4x, the width of the resulting rectangle will be 0.6x, and the perimeter of the resulting rectangle will be:

2 * (2.4x + 0.6x) = 2 * 3x = 6x.

Therefore, the perimeter of the rectangle will decrease by:

100 * (8x – 6x) / 8x = 100 * 2x / 8x = 100/4 = 25%.

Answer: The perimeter of the rectangle will decrease by 25%.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.