2. 1 Polygons Stage 5 Year 9 Press Ctrl-A ©2009 – Not to be sold/Free to use

3. 2 Definition of a Polygon closedthree straight A closed plane figure with three or more straight sides. ClosedOpen

4. 3 Regular Polygons? 345 678 91012 Number Of Sides Click On/Off Triangle Square Pentagon Hexagon Heptagon Octagon Nonagon Decagon Dodecagon They have all angles and all sides equal in size. Polygon Golf Polygon Golf

5. 4 Convex and Non-Convex (Concave) internal less than180 o All internal angles less than 180 o internal greater than180 o Some internal angles greater than 180 o diagonals inside All diagonals lie inside the polygon. diagonals outside Some diagonals lie outside the polygon. Outside Press Press Reflex Angle