Fill in the blanks
The three planes determine a rectangular parallelopiped which has ________ of rectangular faces.
Here, the rectangular parallelepiped is determined by the three planes, ABB’A, AA’D’D, A’B’C’D’.
Here, we have 3 pairs of rectangular faces –
(ABB’A, DCC’D’), (ABCD, A’B’C’D’), (ADD’A’, BCC’B’)