kẻ AM vuông góc vs CD $\Rightarrow AM=\frac{\sqrt{3}}{2}$. Kẻ AH vuông góc vs BM $\Rightarrow$AH vuông góc vs (BCD) $\Rightarrow AH=\frac{a\sqrt{21}}{7}$$\Rightarrow AB=a \Rightarrow VABCD=\frac{a^{3}\sqrt{3}}{6}$
kẻ AM vuông góc vs CD $\Rightarrow AM=\frac{\sqrt{3}}{2}$. Kẻ AH vuông góc vs BM $\Rightarrow$AH vuông góc vs (BCD) $\Rightarrow AH=\frac{a\sqrt{21}}{7}$$\Rightarrow AB=a \Rightarrow VABCD=\frac{a^{3}\sqrt{3}}{18}$
kẻ AM vuông góc vs CD $\Rightarrow AM=\frac{\sqrt{3}}{2}$. Kẻ AH vuông góc vs BM $\Rightarrow$AH vuông góc vs (BCD) $\Rightarrow AH=\frac{a\sqrt{21}}{7}$$\Rightarrow AB=a \Rightarrow VABCD=\frac{a^{3}\sqrt{3}}{
6}$