Question

piramida regulata Sabcd are latura bazei de 18 si inaltimea de 6 cm
aflati aria si volumul

Answer 1

$V= \frac{1}{3}\cdot Ab\cdot h \\ \\ Ab=a^{2}=324 \\ \\ A=Al+Ab \\ \\ Al= \frac{Pb\cdot ap}{2} \\ \\ab= \frac{a}{2}=9\\ \\ ap^{2} =h^{2}+ab^{2} =9^{2} +6^{2} =117 \\ \\ ap= \sqrt{117} \\ Pb=4a=4\cdot 18=72 \\ \\ Al= \frac{72\cdot \sqrt{117}}{2} =389,4\\ \\ A=Al+Ab=324+389,4=713,4 cm^{2} \\ \\ V= \frac{1}{3}\cdot Ab\cdot h= \frac{1}{3}\cdot324\cdot6= 648cm^{3}$