Square prism

Calculate the volume of a four-sided prism 2 dm high, and the base is a trapezoid with bases of 12 cm, 6 cm, a height of 4 cm, and 5 cm long arms.

Correct answer:

V =  0.72 dm³

Step-by-step explanation:

$$\begin{gathered} h=2\text{dm} \\ a=12\text{cm}\to \text{dm}=12:10\text{dm}=1.2\text{dm} \\ c=6\text{cm}\to \text{dm}=6:10\text{dm}=0.6\text{dm} \\ v=4\text{cm}\to \text{dm}=4:10\text{dm}=0.4\text{dm} \\ S=(a+c)\cdot v/2=(1.2+0.6)\cdot 0.4/2=\frac{9}{25}=0.36{\text{dm}}^2 \\ V=S\cdot h=0.36\cdot 2=0.72{\text{dm}}^3 \end{gathered}$$

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