A slice is made parallel to the base of a right rectangular pyramid, as shown. What is the area of the resulting two-dimensional cross-section? Enter your answer in the box.
Rectangular pyramid intersected horizontally by a rectangle. The front edge of the base of the pyramid is labeled 7 millimeters, and the right edge is labeled 4 millimeters. The height of the pyramid is labeled 5 millimeters. The part of the larger rectangle that intersects the pyramid is a smaller gray rectangle. The front side of the smaller rectangle is labeled 3.5 millimeters, and the right side is labeled 2 millimeters.