When to use this calculator
Find the inradius of a regular polygon from side length and side count. The apothem is perpendicular from the centre to a side midpoint.
Explore the quadrilateral & polygon calculators for other questions in this topic. For a related calculation, use the Regular Polygon Area Calculator: Find the area of a regular polygon from side count and side length.
PUTTING IT INTO PRACTICE
Regular Polygon Apothem: 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 |
|---|---|
| Sides (integer) | 6 |
| Side length | 2 |
| Result | 1.732051 units |
- Check the input labels and enter the example values above.
- Apply the relationship: Apothem = side/(2 tan(π/n)).
- The result is 1.732051 units, rounded for display.
How to interpret your result
The apothem is perpendicular from the centre to a side midpoint.
A perimeter measures the outline; area measures the enclosed surface. Regular polygon tools assume equal sides and angles. For a parallelogram or trapezoid, use the height perpendicular to the selected base.
Frequently asked questions
What does regular polygon mean?
It is a polygon with all sides equal and all interior angles equal.
When is the regular polygon apothem calculator useful?
Find the inradius of a regular polygon from side length and side count. The apothem is perpendicular from the centre to a side midpoint.
How do I use the regular polygon apothem calculator?
Enter sides (integer), side length. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Apothem = side/(2 tan(π/n)).
What should I check before using the result?
The apothem is perpendicular from the centre to a side midpoint.
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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