The volume of a rectangular pyramid is given by the formula V = (1/3)Bh, where B is the area of the base and h is the height of the pyramid.
To find the area of the base, we can use the formula for the area of a rectangle: A = lw, where l is the length and w is the width. In this case, the length is 20in and the width is 12in, so the area of the base is:
B = lw = 20in x 12in = 240 sq.in.
Now we can plug in the given values for B and h to find the volume:
V = (1/3)Bh = (1/3)(240 sq.in.)(31in) â 2487.2 cubic inches
Therefore, the volume of the caution warning sign is approximately 2487.2 cubic inches.