3. Line segment AB is drawn on the grid with endpoints at A(0, 8) and B(6, 0) . Using only a straightedge and the grid itself, divide AB into four congruent segments.

      (See explanation)

Step-by-step explanation:

By definition, the volume of a rectangular prism can be found with the following formula:

Where "B" is the area of its base and "h" is the height.

Since the base of a rectangular prism is a rectangle, its area  can be calculated with this formula:

Where "l" is the lenght and "w" is the width.

Let be "x" the lenght of the oatmeal bar, "y" its width and "z" its height.

Then, you can identify that:

If you know the area of the base and the height of the rectangular prism, you only need to substitute values into the formula and then evaluate, in order to calculate its volume. Then: