Fire tank

1428 hl of water is filled in a block-shaped fire tank with the edges of the base 12 m and 7 m. Calculate the area of water-wetted areas.

Correct answer:

S =  148.6 m²

Step-by-step explanation:

$$\begin{gathered} a=12\text{m} \\ b=7\text{m} \\ V=1428\text{hl}\to {\text{m}}^3=1428:10{\text{m}}^3=142.8{\text{m}}^3 \\ {S}_1=a\cdot b=12\cdot 7=84{\text{m}}^2 \\ V=S_1\cdot c \\ c=V/S_1=142.8/84=\frac{17}{10}=1.7\text{m} \\ S=S_1+2\cdot (a+b)\cdot c=84+2\cdot (12+7)\cdot 1.7=148.6{\text{m}}^2 \end{gathered}$$

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