Question

Daca aria unui tetraedru regulat e
$9\sqrt{3}$
atunci suma lungimilor muchiilor tetraedrului va fi egala cu...

Answer 1

[tex]A_{t}=9\sqrt3\;cm^2\;\\ \\ \Rightarrow\;4\,\cdot\,A_{f}\,=\,9\sqrt3(cm^2)\\ \\ A_{f}\,=\,\frac{9\sqrt3}{4}\,=\,\frac{l^2\sqrt3}{4}\,\Rightarrow\,l^2=9\\ \\ deci:\;l=muchia\;tetraedrului\;regulat=3\,cm\,.[/tex]