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Regular pentagon

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Geometry (2d) index
Regular pentagon diagram
calc
Regular pentagons have internal angles of 108°. This calc relates the side length to the corner-center distance, edge-center distance, and area.
Side length

Corner-center distance
Side-center distance
Area
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notes
Regular pentagons (i.e. those with all side lengths and angles equal) can be constructed using only a compass and straight-edge. These calculations are done by the application of simple ratios calculated from trigonometry.