Regular triangular prism

Calculate the surface area of the body of a regular triangular prism when the length of its base edge is 6.5 cm, and its height is 0.2 m.

Correct answer:

S =  390 cm²

Step-by-step explanation:

$$\begin{gathered} a=6.5\text{cm} \\ h=0.2\text{m}\to \text{cm}=0.2\cdot 100\text{cm}=20\text{cm} \\ {h}_2=\sqrt{3}/2\cdot a=\sqrt{3}/2\cdot 6.5\doteq 5.6292\text{cm} \\ {S}_2=a\cdot h=6.5\cdot 20=130{\text{cm}}^2 \\ S=3\cdot S_2=3\cdot 130=390{\text{cm}}^2 \end{gathered}$$

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