Cho hình chóp S.ABC, có \(\widehat{ASB\: =}90^0,\widehat{BSC}=60^0,\widehat{CSA}=120^0,SA=a,SB=a\sqrt{3},SC=a\sqrt{2}.\) Tính thể tích khối chóp S.ABC
A. \(\dfrac{a^2\sqrt{3}}{6}\)
B. \(\dfrac{a^2\sqrt{3}}{2}\)
C. \(\dfrac{a^2\sqrt{2}}{6}\)
D. \(\dfrac{a^2\sqrt{3}}{4}\)
\(V=\dfrac{a.a\sqrt{3}.a\sqrt{2}}{6}.\sqrt{1+2cos90^0.cos60^0.cos120^0-cos^290-cos^260-cos^2120}=\dfrac{a^3\sqrt{3}}{6}\)