Calculator Inputs and Outputs
Inputs
- Side length (units) — example: 5
Results
- Circumradius (units)
- Apothem (units)
- Perimeter (units)
Formula used
Circumradius = side ÷ (2 × sin(π/72)); apothem = side ÷ (2 × tan(π/72)).
How to Use the Regular 72-Sided Polygon Radius Calculator
Enter the requested values and select Calculate Regular 72-Sided Polygon Radius. The default inputs provide a complete working example that can be replaced with your own values.
Formula
Circumradius = side ÷ (2 × sin(π/72)); apothem = side ÷ (2 × tan(π/72)).
Understanding the Results
The primary answer appears first. Supporting results show related quantities, intermediate values, or comparisons that help you check the estimate.
Accuracy Tips
- Use consistent units and retain extra precision until the final rounded result.
- Use measured or verified inputs.
- Recalculate whenever an assumption changes.
Important Note
This calculator is an informational planning tool. Confirm critical financial, medical, construction, scientific, tax, legal, or safety decisions with an appropriately qualified professional.
Calculation Standards
This tool uses documented formulas and high-precision internal values. Displayed results may be rounded for readability. Review the assumptions and verify important decisions with a qualified professional.
Read our calculation methodology