The (Example) and ①, ② and ③ in Fig. P are the figures which cut off a 3cm cube as shown in a lower figure at one plane and looked at the solid below a cut surface from the direction of A (right above) and B (front).
The portion into which the cut surface is in sight is shaded by slant line.
As for ①，② and ③, as shown in Fig. Q, write a cut surface to the sketch and shade by slant line.
Moreover, find the volume of the solid below a cut surface.
Noted that the volume of a pyramid is calculated by (base area) x (height) x 1/3.