Question

Сколько понадобится краски,чтобы покрасить поверхность бруса,изображённого на рисунке,если для покраски 1 дм2 поверхности нужно 2 г краски? Если дина 40см ширина 30см и высота 30см

Answer 1

40см=4дм; 30см=3дм
2×(4×3+4×3+3×3)=2×(12+12+9)=66дм2
Площадь всей поверхности бруса
66×2=132г краски понадобится

Answer 2

Calculating the Amount of Paint Needed

To calculate the amount of paint needed to cover the surface of the depicted wooden block, we can use the formula:

Amount of paint (in grams) = Surface area to be painted (in square centimeters) × Amount of paint needed per square centimeter (in grams)

Given: - Length = 40 cm - Width = 30 cm - Height = 30 cm - Amount of paint needed per square centimeter = 2 grams

Surface Area Calculation

The surface area of the wooden block can be calculated using the formula for the total surface area of a cuboid:

Total Surface Area = 2lw + 2lh + 2wh

Where: - l = length - w = width - h = height

Substituting the given values: - l = 40 cm - w = 30 cm - h = 30 cm

Total Surface Area = 2(40×30) + 2(40×30) + 2(30×30) Total Surface Area = 2400 + 2400 + 1800 Total Surface Area = 6600 square centimeters

Amount of Paint Needed

Now, using the formula mentioned earlier:

Amount of paint = 6600 square centimeters × 2 grams Amount of paint = 13200 grams

Therefore, to paint the surface of the depicted wooden block, 13200 grams of paint will be needed.