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Word Problems: Prisms and Cylinders
Volume word problems about prisms and cylinders ask you to identify the shape, pick base area times height for a prism or pi r squared h for a cylinder, and calculate with the given measurements. Worked through with a cylindrical tank example finding a capacity of about 62.8 cubic meters.
Worked example: a cylindrical tank
Since the tank is a cylinder, use V = πr²h. Squaring the radius gives 2² = 4, multiplying by π gives about 12.57, and multiplying by the height of 5 gives a capacity of about 62.8 cubic meters.
A general problem-solving approach
- Identify the shape: is it a prism (flat, matching ends) or a cylinder (circular ends)?
- Write down what you know: base dimensions or radius, and height.
- Apply the matching formula from volume of a prism or volume of a cylinder.
- Check the units — the answer is always in cubic units.
Comparing volumes
Some problems ask you to compare a prism's capacity to a cylinder's, such as which container holds more. Calculate each volume separately using its own formula, then compare the results directly since both answers are already in the same cubic units.