A regular decagon has ten equal sides and equal interior angles. The area formula uses side length and the central angle structure of a regular polygon.
⚠Use a positive side length. This page does not calculate irregular decagons.
How Decagon Area Works
Connecting the center to each vertex forms ten equal triangles. The calculator combines those triangle areas and also reports perimeter and apothem.
Ten Sides
A decagon has ten sides.
Regular Polygon
All sides and angles match.
Perimeter
Perimeter equals 10s.
Apothem
Center-to-side distance supports area.
💡 Example: For s=4, area is about 123.107, perimeter is 40, and apothem is 6.155.
Applications of Decagon Area
Design GridsTokensArchitectureGeometry Worksheets
Frequently Asked Questions
What is a decagon area calculator?▼
It calculates the area of a regular ten-sided polygon from side length.
What formula does it use?▼
It uses A = ns²/(4 tan(π/n)) with n = 10.
How do I use this calculator?▼
Enter the side length and click Calculate to get area, perimeter, and apothem.
Is this for regular decagons only?▼
Yes. Irregular decagons require coordinate or decomposition methods.
Where is decagon area used?▼
It is used in geometry, design grids, tokens, architecture, and polygon worksheets.
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