Question

Периметр прямоугольника 40 дм.Найди площадь прямоугольника,если его длина в 3 раза больше ширины

Answer 1

2*((х*3)+х)=40
2*(3х+х)=40
6х+2х=40
8х=40
х=5 (дм) - ширина прямоугольника
5*(5*3)=75 дм2
Отв.: S=75 дм2

Answer 2

Calculation of the Rectangle's Area

To find the area of a rectangle, we need to know its perimeter and the relationship between its length and width. In this case, we are given that the perimeter of the rectangle is 40 dm and that the length is three times the width.

Let's break down the problem step by step:

1. Let's assume the width of the rectangle is x dm. 2. According to the given information, the length of the rectangle is three times the width, so the length would be 3x dm. 3. The perimeter of a rectangle is calculated by adding the lengths of all its sides. In this case, the perimeter is given as 40 dm, so we can set up the equation: 2(x + 3x) = 40 Simplifying the equation, we get: 2(4x) = 40 8x = 40 x = 5 Therefore, the width of the rectangle is 5 dm. 4. Now that we know the width, we can calculate the length: Length = 3x = 3 * 5 = 15 Therefore, the length of the rectangle is 15 dm. 5. Finally, we can calculate the area of the rectangle using the formula: Area = Length * Width = 15 * 5 = 75 Therefore, the area of the rectangle is 75 square dm.

So, the area of the rectangle is 75 square dm.