[scheduled:: 2025-01-17]
Polygon Problems
Links and useful resources
- gr10's Geometry >>>START HERE<<<
- AoPS Alcumus
- Handwritten math converter
- Big Ideas Geometry textbook
- GeoGebra Online Geometry Constuction Tool
- Two-column math templates
- Proofs unit slides from mathgiraffe.com
- Proofs unit printables for two-column proofs
Concept summary and connections
- area and perimeter of polygons
- interior angles in polygons
- exterior angles of polygons
- convex and concave polygons
- regular and irregular polygons
Worked examples
- 9.10: Diagonals BD and CE of regular pentagon ABCDE meet at Q. Find angle BQE. (A is vertex on top in the diagram)
- 9.11: Find the number of diagonals in a polygon with n sides. Start with a few examples, build a table, look for a pattern, then prove the pattern.
- All interior angles of hexagon ABCDEF have measure 120. ABCDEF has sides AB=BC=DE=EF=2 and CD=AF=4. What is the area of the hexagon?
Things to look for that frequently help:
- Parallel lines
- Congruent or similar triangles
- Equal angles
- Complementary or supplementary angles
- Places where an additional line could give you one of those things
- Angles on the extensions of lines
- BEWARE of assuming a polygon is regular - if it doesn't say so, it isn't so!
Media resources
- Youtube search for "area and perimeter of polygons"
- Youtube search for "interior angles in polygons"
- Youtube search for "exterior angles of polygons"
- Youtube search for "convex and concave polygons"
- Youtube search for "regular and irregular polygons"