The concrete basement

The concrete base has a square base a = 90 cm and is 0.2 m high. How many kg of concrete did we use to build it if the concrete density is ρ=2200 kg/m³?

Correct answer:

m =  356.4 kg

Step-by-step explanation:

$$\begin{gathered} a=90\text{cm}\to \text{m}=90:100\text{m}=0.9\text{m} \\ h=0.2\text{m} \\ V=a^2\cdot h=0.9^2\cdot 0.2=\frac{81}{500}=0.162{\text{m}}^3 \\ \rho =2200{\text{kg/m}}^3 \\ m=\rho \cdot V=2200\cdot 0.162=356.4\text{kg} \end{gathered}$$

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