Tetrahedral pyramid

It is given a regular tetrahedral pyramid with a base edge of 6 cm and a height of pyramid 10 cm. Calculate the length of its side edges.

Correct answer:

s =  10.8628 cm

Step-by-step explanation:

$$\begin{gathered} a=6\text{cm} \\ h=10\text{cm} \\ u=a\cdot \sqrt{2}=6\cdot \sqrt{2}=6\sqrt{2}\doteq 8.4853 \\ s=\sqrt{h^2+(u/2{)}^2}=\sqrt{10^2+(8.4853/2{)}^2}=\sqrt{118}=10.8628\text{cm} \end{gathered}$$

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