Cylindrical 27733

The cylindrical silo has a diameter of 4 m and a height of 7 m. For how many square meters is it necessary to buy paint to paint against corrosion (we paint the silo only from the outside)?

Correct answer:

S =  113.0973 m²

Step-by-step explanation:

$$\begin{gathered} D=4\text{m} \\ h=7\text{m} \\ r=D/2=4/2=2\text{m} \\ {S}_1=\pi \cdot r^2=3.1416\cdot 2^2\doteq 12.5664{\text{m}}^2 \\ {S}_2=\pi \cdot D\cdot h=3.1416\cdot 4\cdot 7\doteq 87.9646{\text{m}}^2 \\ S=2\cdot S_1+S_2=2\cdot 12.5664+87.9646=113.0973{\text{m}}^2 \end{gathered}$$

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