The depth is what makes this a three dimensional figure since there are three dimensions: length, width, and depth! All three of these dimensions are used to find the volume of a rectangular prism.
START WITH 1 COUNT BY ONES 1, 2, 3, 4, 5, 6
START WITH 8 COUNT BY ONES 8, 9, 10, 11, 12, 13
90 degrees converted to radians is pi/2 or π/2 radians.
4 because that is what's multiplied throughout