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Volumul unui tetraedru reguat cu muchia de 3 cm este de cati cm la a 3-a ?

Răspuns :

V = ( Aria bazei x inaltimea ) : 3

Aria bazei = [tex] \frac{l^{2} \sqrt{3} }{4} = \frac{9 \sqrt{3} }{4} [/tex]

Inaltimea = [tex] \frac{l \sqrt{6} }{3} = \frac{3 \sqrt{6} }{3} = \sqrt{6} [/tex]

V = [tex]\frac{\frac{9 \sqrt{3} }{4}* \sqrt{6}}{3} = \frac{9 \sqrt{18} }{12} = \frac{27 \sqrt{2} }{12} = \frac{9 \sqrt{2} }{4} [/tex] [tex]cm^{3} [/tex]