Cylindrical 83193

How much concrete is needed to pour 8 concrete columns with a square base: a = 38 cm, the height of the columns being 6.2 m? Each column has a cylindrical cavity with a diameter of 15 cm.

Correct answer:

V =  6.2857 m³

Step-by-step explanation:

$$\begin{gathered} n=8 \\ a=38\text{cm}\to \text{m}=38:100\text{m}=0.38\text{m} \\ h=6.2\text{m} \\ d=15\text{cm}\to \text{m}=15:100\text{m}=0.15\text{m} \\ r=d/2=0.15/2=\frac{3}{40}=0.075\text{m} \\ {S}_1=a^2-\pi \cdot r^2=0.38^2-3.1416\cdot 0.075^2\doteq 0.1267{\text{m}}^2 \\ {V}_1=S_1\cdot h=0.1267\cdot 6.2\doteq 0.7857{\text{m}}^3 \\ V=n\cdot V_1=8\cdot 0.7857=6.2857{\text{m}}^3 \end{gathered}$$

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