UNDERSTANDING SHAPES (Including Polygons)
165. The Regular Polygon's Secret · Angles, sides, and the magic of n
Exterior + Interior = 180°, and sum of all exterior angles = 360°.
This diagram shows a regular n-sided polygon inscribed in a circle.
• Drag vertex V to change the polygon's size and rotation
• Drag the green slider to change the number of sides (n)
• Each exterior angle = 360° ÷ n (purple arc)
• Each interior angle = 180° − 360°/n (yellow arc)
• Together they form a linear pair — always adding to 180°.
For a regular hexagon (n = 6): exterior = 60°, interior = 120°.
For a regular decagon (n = 10): exterior = 36°, interior = 144°.