O piramida triunghiulara regulata are aria laterala de 195√3 cm² si aria totala de 270√3 cm². Calculati volumul piramidei.

Răspuns :

At=Al+Ab
270[tex] \sqrt{3} [/tex]=195[tex] \sqrt{3} [/tex]+Ab
Ab=270[tex] \sqrt{3} [/tex]-195[tex] \sqrt{3} [/tex]
Ab=75[tex] \sqrt{3 } [/tex]
Ab=[tex] \frac{ l^{2} \sqrt{3} }{4}=75 \sqrt{3} [/tex]
In final[tex] l^{2} =10 \sqrt{3} [/tex]
OM=[tex] \frac{1}{3}* \frac{10 \sqrt{3}* \sqrt{3} }{2} =5[/tex]
[tex]Al=\frac{Pb*ap }{2} Pb=195 \sqrt{3} ; VO=13[/tex][tex]VO^{2}= 13^{2} - 5^{2} ;VO=12[/tex][tex]V= \frac{Ab*h}{3}= \frac{75 \sqrt{3}*12 }{3} .Se simplifica iar in final V=300 \sqrt{3} cm^{3} [/tex]