When to use this calculator
Find the sloping side length of a truncated cone. Assumes a right circular conical frustum.
Explore the volume & surface area calculators for other questions in this topic. For a related calculation, use the Hemisphere Surface Area Calculator: Find the combined curved and base surface area of a hemisphere.
PUTTING IT INTO PRACTICE
Frustum Slant Height: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Larger radius | 5 |
| Smaller radius | 2 |
| Perpendicular height | 4 |
| Result | 5 units |
- Check the input labels and enter the example values above.
- Apply the relationship: Slant height = √((larger radius−smaller radius)²+height²).
- The result is 5 units, rounded for display.
How to interpret your result
Assumes a right circular conical frustum.
Volume and surface area have different units and answer different questions. Use internal dimensions for capacity. A closed-solid surface area includes bases and lids unless the calculator explicitly describes an open shape.
Frequently asked questions
Should I use internal or outside measurements?
Use internal measurements for capacity and outside measurements for covering the exterior. Match the formula to the part being measured.
When is the frustum slant height calculator useful?
Find the sloping side length of a truncated cone. Assumes a right circular conical frustum.
How do I use the frustum slant height calculator?
Enter larger radius, smaller radius, perpendicular height. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Slant height = √((larger radius−smaller radius)²+height²).
What should I check before using the result?
Assumes a right circular conical frustum.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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