Capacity in gallons of a rectangle 44 X 35 X 16?

Answer 1

This question cannot be answered.

First, a rectangle is a two dimensional, or plane figure and so has 0 volume - whether measured in gallons, litres or any other units.

Second, even if the object were a 3-dimensional cuboid, there are no units give. There is no way to tell whether it is 44 inch * 35 inch * 16 inch or 44 ft * 35 ft * 16 ft (which would be a volume 1728 as large), or some othe units.