Question

Длина огорода 70 дм, а ширина короче на 2 м. Вокруг огорода вырыли канаву, ее периметр 40 м, Найди ширину канавы

Answer 1

Переведём длину в метры.

1 м = 10 дм.

70 дм = 7 м.

Вычислим ширину огорода.

7 - 2 = 5 м - ширина огорода.

Так как канаву вырыли на расстоянии 2 метра от каждой стороны, то длина и ширина увеличились на 2 метра с двух сторон. Вычислим длину и ширину нового прямоугольника, образованного канавой.

7 + 2 + 2 = 11 м - длина нового прямоугольника с канавой.

5 + 2 + 2 = 9 м - ширина нового прямоугольника с канавой.

Вычислим периметр прямоугольника, сложив две стороны и умножив на 2.

( 11 + 9 ) * 2 = 40 см - периметр прямоугольника с канавой.

Ответ: 40 см.

Answer 2

Problem Analysis

We are given the length of a garden, which is 70 dm, and the width of the garden, which is 2 meters shorter than the length. Additionally, a trench was dug around the garden, and the perimeter of the trench is 40 meters. We need to find the width of the trench.

Solution

Let's start by finding the width of the garden. We know that the width is 2 meters shorter than the length. So, if the length is L, then the width is L - 2.

Given that the length of the garden is 70 dm, we can substitute L = 70 into the equation to find the width:

Width of the garden = Length of the garden - 2 = 70 - 2 = 68 dm

Next, we need to find the width of the trench. We are given that the perimeter of the trench is 40 meters. The perimeter of a rectangle is given by the formula:

Perimeter = 2 * (Length + Width)

In this case, the perimeter of the trench is 40 meters, and we know the length of the garden is 70 dm. We need to convert the length to meters before substituting it into the formula. Since 1 meter is equal to 10 decimeters (dm), we can convert the length as follows:

Length of the garden in meters = Length of the garden in decimeters / 10 = 70 / 10 = 7 meters

Now we can substitute the values into the formula to find the width of the trench:

40 = 2 * (7 + Width of the trench)

Simplifying the equation:

40 = 14 + 2 * Width of the trench

Subtracting 14 from both sides:

26 = 2 * Width of the trench

Dividing both sides by 2:

Width of the trench = 26 / 2 = 13 meters

Therefore, the width of the trench is 13 meters.

Answer

The width of the trench is 13 meters.