A graduated cylinder is filled to 32.6 mL with water and a piece of granite
is placed in the cylinder, displacing
the level to 40.7 mL. What is the
volume of the granite piece in cubic
centimeters?

The method use to determine the volume of the granite is more commonly called water-displacement method. A more common method that is usually used for irregularly shaped objects. To determine the volume of the granite, we just have to subtract the initial volume from the final volume. That is,
                     volume of granite = 40.7 mL - 32.6 mL = 8.1 mL