A magnesium alloy contains the following volumes of each element: 341.2 cubic decimeters of magnesium, 30.96 cubic decimeters of aluminum, 488.0 cubic centimeters of manganese, and 672.0 cubic centimeters of zinc. Find the percent composition by volume of magnesium. Round the answer to the nearest hundredth percent.
First, find the total volume of the alloy by adding the volumes of each element: 341.2 cubic decimeters + 30.96 cubic decimeters + 488.0 cubic centimeters + 672.0 cubic centimeters = 1543.16 cubic centimeters
Then divide the volume of magnesium by the total volume and multiply by 100% to express the composition as a percentage: 341.2 cubic decimeters / 1543.16 cubic decimeters * 100% = 22.11%. Answer: \boxed{22.11\%}.