Rectangular Prism
The volume of a rectangular prism is (height)(lenght)(depth). This is true because you are measuring the number of cubic units in the Prism. A rectangular Prism is a 3 Dimensional object so there must be 3 aspects (Dimensions) we must consider. So we start with the area of a rectangle which is (base)(height or length). A rectangle is a 2D figure so if we add the dimension of depth we get a 3D figure.