1. Polygon Definition Bounded by a closed circuit of straight-line segment. Term Edge : straight line segment Vertices : points

2. Polygon Type of polygon Convex : edges intersect only at vertices Regular polygons : edges all of length, vertex angle and inscribed in a circle Concave Stellar or star polygon : edges of polygon intersect at point in the addition to the vertex points

3. Properties At least three edges to enclose a finite area V – E = 0 V : vertices quantity, E : edges quantity T = V – 2 T : triangulation

4. Properties Angle’ Sum of interior angles of polygon Sum of exterior angles of polygon(only convex)

5. Properties Line’ Perimeter of regular polygon perimeter = EL E : edges quantity, L : edge length Sum of length Position’

6. Properties Area’ Area of a regular polygon Viewpoint on vector

7. Special Polygon Convex Hull convex polygon has equal edges concave polygon has fewer edges

8. Polygon Symmetry of polygons Reflection Inversion Rotation Containment 1. Determinate Min, Max Box 2. straddle yt 3. check extend point of intersection