Question

Периметр прямоугольника равен 40 дм. найди площадь прямоугольника, если его длина в 3 раза больше ширины. выполни схему и реши задачу.

Answer 1

Ширина x,длина 3x.периметр P=2*(x+3x)=2*4x=8,По условию задачи 8x=40см.Тогда x=5см.Ширина прямоугольника 5см,длина 3*5=15см.Его площадь S=5*15=75кв.см.

Answer 2

X дм - ширина
3x дм- длина
x+x+3x+3x=40
8x=40
x=40:8
x=5 дм ширина, 5*3=15 дм - длина
5*15=75 дм квадратных площадь

Answer 3

Problem Analysis

We are given that the perimeter of a rectangle is 40 dm and that the length of the rectangle is 3 times the width. We need to find the area of the rectangle.

Solution

Let's assume the width of the rectangle is w dm. According to the problem, the length of the rectangle is 3 times the width, so the length would be 3w dm.

The perimeter of a rectangle is given by the formula: perimeter = 2(length + width).

We can substitute the given values into the formula and solve for the width: 40 = 2(3w + w).

Simplifying the equation: 40 = 2(4w), 40 = 8w, w = 5.

Now that we have the width, we can find the length: length = 3w = 3(5) = 15.

The area of a rectangle is given by the formula: area = length * width.

Substituting the values: area = 15 * 5 = 75.

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

Diagram

Here is a diagram to help visualize the problem:

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The length of the rectangle is 15 dm and the width is 5 dm.

Answer

The area of the rectangle is 75 square dm.

Please let me know if there is anything else I can help you with.