Similar Solids and Cavalieri's Principle — Worked Examples
These examples develop the square-cube law and Cavalieri reasoning from direct scaling to inverse and engineering applications.
Example 1: Linear, area, and volume scale factors
A geometric model is enlarged so every corresponding length is multiplied by . Determine the corresponding area and volume multipliers.
Step-by-Step Solution
0 of 3 Steps CompletedExample 2: Volume of a similar storage vessel
A prototype vessel has capacity . A geometrically similar vessel is built at twice every internal linear dimension. Determine its capacity.
Step-by-Step Solution
0 of 2 Steps CompletedExample 3: Recover a linear scale factor from area ratio
Two similar solids have corresponding surface areas and . Find the linear scale factor from the smaller to the larger solid.
Step-by-Step Solution
0 of 2 Steps CompletedExample 4: Recover a dimension from volume ratio
Two similar concrete specimens have volumes and . A corresponding edge of the smaller specimen is . Determine the matching edge of the larger specimen.
Step-by-Step Solution
0 of 2 Steps CompletedExample 5: Mass scaling for the same material
A solid bronze model has mass . A geometrically similar model of the same bronze is made with every dimension times the original. Determine its mass.
Step-by-Step Solution
0 of 2 Steps CompletedExample 6: Similar geometry but different material density
A steel model is geometrically similar to an aluminum prototype at linear scale factor . Let the steel density be and aluminum density be . Determine the steel-to-aluminum mass ratio.
Step-by-Step Solution
0 of 3 Steps CompletedExample 7: Right and oblique prism volumes
A right prism and an oblique prism have identical base areas of and the same perpendicular height of . The oblique prism has lateral edges long. Compare their volumes.
Step-by-Step Solution
0 of 2 Steps CompletedExample 8: Same base and height do not guarantee equal volume
A prism and a pyramid have the same base area and the same perpendicular height . Show why these data alone do not satisfy Cavalieri's conclusion.
Step-by-Step Solution
0 of 3 Steps CompletedExample 9: Similar section inside a cone
A cone is high with base area . Determine the area of a section parallel to the base located from the apex.
Step-by-Step Solution
0 of 2 Steps CompletedExample 10: Volume fraction of an apex pyramid
A plane parallel to the base of a pyramid is located at of the full height measured from the apex. What fraction of the full pyramid volume lies between the apex and this plane?
Step-by-Step Solution
0 of 2 Steps CompletedExample 11: Surface-area-to-volume ratio under enlargement
A family of similar solids is enlarged by a linear factor . Determine the factor by which its surface-area-to-volume ratio changes.
Step-by-Step Solution
0 of 3 Steps CompletedExample 12: Non-uniform coordinate scaling
A rectangular solid has original volume . Its , , and dimensions are independently scaled by , , and , respectively. Determine the new volume and state whether the new solid is necessarily similar to the original.
Step-by-Step Solution
0 of 3 Steps CompletedScaling check
Always define which solid is the reference before computing . Reversing the scale-factor direction reverses every derived ratio. For Cavalieri comparisons, equality at only one cross-section is insufficient; the cross-sectional areas must match at every corresponding level.