Frustums — Worked Examples
These problems use both direct frustum formulas and similarity reconstruction. Check whether the problem asks for perpendicular height, slant height, capacity, lateral area, total area, or material volume.
Example 1: Volume of a conical frustum
A conical frustum has larger radius , smaller radius , and perpendicular height . Determine its volume.
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0 of 2 Steps CompletedExample 2: Slant height and lateral area of a conical frustum
Use the frustum from Example 1. Determine its slant height and curved lateral area.
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0 of 2 Steps CompletedExample 3: Total closed surface area of a conical frustum
For the frustum in Examples 1–2, determine the total closed surface area.
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0 of 2 Steps CompletedExample 4: Reconstruct the removed cone
A conical frustum has , , and height . Determine the height of the small cone removed from the apex and the original full-cone height.
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0 of 3 Steps CompletedExample 5: Verify frustum volume by difference of cones
Use the reconstructed geometry from Example 4 to compute the frustum volume by subtraction.
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0 of 3 Steps CompletedExample 6: Square pyramidal frustum volume
A square pyramidal frustum has lower side , upper side , and perpendicular height . Determine its volume.
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0 of 2 Steps CompletedExample 7: Lateral area of a regular square frustum
Use the square frustum from Example 6. Determine its lateral area.
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0 of 3 Steps CompletedExample 8: Inverse height from conical-frustum capacity
A conical frustum has , , and required capacity . Determine the perpendicular height.
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0 of 2 Steps CompletedExample 9: Hollow tapered component material volume
A hollow conical-frustum shell has outer radii and , inner radii and , and common perpendicular height . Determine the material volume.
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0 of 3 Steps CompletedExample 10: Prismatoidal verification of a conical frustum
For a conical frustum with , , and , verify its volume using the end areas and midpoint area.
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0 of 3 Steps CompletedExample 11: Limiting case as a frustum becomes a cylinder
A conical-frustum formula is evaluated with and . Show that it reduces to the cylinder volume.
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0 of 2 Steps CompletedExample 12: Uniformly scale a frustum
A frustum has volume and total surface area . A similar frustum is built with every linear dimension multiplied by . Determine the new volume and area.
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0 of 2 Steps CompletedFrustum calculation check
Confirm that the two bases are parallel and similar before using the direct frustum formula. Use perpendicular height for volume and slant height for lateral area. In hollow components, subtract the inner frustum volume only when the inner and outer geometries are described consistently over the same axial height.