Figure 1 shows the cross section of a right rectangular prism parallel to its base.

The cross section is a rectangle.

The cross section of any right prism parallel to its base is congruent to the base. |

Figure 2 shows the cross section of a right rectangular prism perpendicular to its base.

The cross section is a rectangle.

Figure 3 shows the cross section of a right rectangular prism along its diagonal.

The cross section is a rectangle.

Note that not all cross sections of a rectangular prism are rectangles.

Figure 4 shows the cross section of a right rectangular pyramid parallel to its base.

The cross section is a rectangle.

Figure 5 shows the cross section of a right rectangular pyramid through its

apex and perpendicular to its base.

The cross section is a triangle.

Figure 6 shows the cross section of a right rectangular pyramid perpendicular to its base, not through the apex.

The cross section is a trapezoid.