Cho hình chóp S.ABC có ASB=CSB=

B

- Hướng dẫn giải

Đáp án B

$\begin{array}{l}A(0;\frac{-a\sqrt{2}}{2};0);\\ S(0;0;\frac{a\sqrt{2}}{2});\\ B(\frac{a\sqrt{2}}{2};0;0);C(0;\frac{a\sqrt{2}}{2};0)\\ \overrightarrow{SB}(\frac{a\sqrt{2}}{2};0;-\frac{a\sqrt{2}}{2})\\ \overrightarrow{SC}(0;\frac{a\sqrt{2}}{2};-\frac{a\sqrt{2}}{2})\\ \overrightarrow{n_{SBC}}=\text{[}\overrightarrow{SB},\overrightarrow{SC}\text{]}=(1;1;1)\\ \left(SBC\right):x+y+z-\frac{a\sqrt{2}}{2}=0\\ d(A;SBC)=\frac{a\sqrt{2}}{\sqrt{3}}=\frac{a\sqrt{6}}{3}\\ \end{array}$