Estimate the volumes of a) the cylinder b) the ring

Volume of the cylinder: The initial water level is at 20 mL, and after the cylinder is submerged, the water level rises to 30 mL. Therefore, the volume of the cylinder is 30 mL - 20 mL = 10 mL.

Volume of the ring: The initial water level is at 70 mL, and after the ring is submerged, the water level rises to 72 mL. Therefore, the volume of the ring is 72 mL - 70 mL = 2 mL.