Decagon Calculator: Find Area, Perimeter, and Angles Instantly

Calculate Regular Decagon Properties

Unlock the power of ten-sided polygons with our easy-to-use Decagon Calculator. Whether you need to find the area, perimeter, or interior angles, simply input the side length and get precise results for any regular decagon. Perfect for geometry, design, and engineering tasks!

Formula:

For a regular decagon with side length (s):

  • Area (A) = 2.5 × s² × cot(18°) (where cot(18°) ≈ 3.0776835)
  • Perimeter (P) = 10 × s
  • Interior Angle (I) = (10 - 2) × 180° / 10 = 144°

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