Đáp án:
$V_{ACB'D'}=\dfrac13V$
Giải thích các bước giải:
Ta có:
$V_{ABCD.A'B'C'D'}= V_{A.A'B'D'} + V_{C.B'C'D} + V_{B'.ABC} + V_{D'.ACD} + V_{ACB'D'}$
$\Leftrightarrow V = \dfrac13S_{A'B'D'}.AA' + \dfrac13S_{B'C'D'}.CC' + \dfrac13S_{ABC}.BB' + \dfrac13S_{ACD}.DD' + V_{ACB'D'}$
$\Leftrightarrow V = \dfrac16S_{A'B'C'D'}.AA' + \dfrac16S_{A'B'C'D'}.CC' + \dfrac16S_{ABCD}.BB' +\dfrac16S_{ABCD}.DD' + V_{ACB'D'}$
$\Leftrightarrow V =\dfrac16V + \dfrac16V + \dfrac16V + \dfrac16V + V_{ACB'D'}$
$\Leftrightarrow V_{ACB'D'}=\dfrac13V$
