Block-shaped 32591

Štěpán painted a block-shaped steel board measuring 2.2 m, 1.5 m, and 1.6 m twice with a protective coating. How many kilograms of paint would he consume if he used 120g of paint per 1m²?

Correct answer:

x =  4.4256 kg

Step-by-step explanation:

$$\begin{gathered} a=2.2\text{m} \\ b=1.5\text{m} \\ c=1.6\text{m} \\ n=2 \\ {S}_1=2\cdot (a\cdot b+b\cdot c+c\cdot a)=2\cdot (2.2\cdot 1.5+1.5\cdot 1.6+1.6\cdot 2.2)=\frac{461}{25}=18.44{\text{m}}^2 \\ \rho =120\text{g}\to \text{kg}=120:1000\text{kg}=0.12\text{kg} \\ {S}_2=n\cdot S_1=2\cdot 18.44=\frac{922}{25}=36.88{\text{m}}^2 \\ x=S_2\cdot \rho =36.88\cdot 0.12=4.4256\text{kg} \end{gathered}$$

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