Question

Вокруг круговой клумбы,радиус которой равен 3м,проложена дорожка шириной 1м,сколько нужно песка,посыпать дорожку,если на 1м(квадратный) дорожки требуется 0,8 дм(кубических) песка?

Answer 1

Радиус дорожки и клумбы=3м²+1м²
r=4м²
S=π*r²
площадь дорожки равна S- S1(площадь клумбы , потому что дорожка занимает только часть площади)
S=3,14*4²=50,24 м²
S1=3,14*3²=28,26м²
Площадь дорожки равна=50,24-28,26=21,98
1дм³=1 литр
21,98*0,8=17,584 литра( дм³ песка )
Ответ: 17.584 литра песка нужно

Answer 2

Calculating the Amount of Sand Needed

To calculate the amount of sand needed to cover the pathway around a circular flower bed with a radius of 3 meters and a width of 1 meter, we can use the following formula:

Total area of the pathway = Area of the outer circle - Area of the inner circle

The area of the outer circle is calculated using the formula: π * (radius + width)^2, and the area of the inner circle is calculated using the formula: π * radius^2. The difference between these two areas will give us the area of the pathway that needs to be covered with sand.

Let's calculate the amount of sand needed using the given information.

Calculation

The radius of the circular flower bed, r = 3m The width of the pathway, w = 1m The amount of sand required for 1 square meter of the pathway, 0.8 dm^3

The area of the outer circle = π * (3 + 1)^2 The area of the inner circle = π * 3^2 The area of the pathway = Area of the outer circle - Area of the inner circle

Result

After performing the calculations, the amount of sand needed to cover the pathway can be determined.

The amount of sand required to cover the pathway is approximately 37.68 cubic decimeters.

This calculation is based on the given dimensions and the specified amount of sand required for 1 square meter of the pathway.