Summary
Polygons are closed shapes with straight sides. They have specific properties related to their interior and exterior angles.
- Triangle — A polygon with three sides. Example: The sum of interior angles is 180°.
- Exterior Angle of a Triangle — Equal to the sum of the two opposite interior angles. Example: e° = a° + b°.
- Quadrilateral — A polygon with four sides. Example: The sum of interior angles is 360°.
- Regular Polygon — A polygon with all sides and angles equal. Example: The sum of interior angles of a hexagon is 720°.
- Sum of Exterior Angles — Always 360° for any polygon. Example: Each exterior angle of a regular hexagon is 60°.
Exam Tips
Key Definitions to Remember
- Sum of interior angles of a triangle is 180°
- Sum of interior angles of a quadrilateral is 360°
- Sum of exterior angles of any polygon is 360°
Common Confusions
- Confusing interior and exterior angles
- Miscalculating the sum of angles in polygons with more than four sides
Typical Exam Questions
- What is the sum of interior angles of a triangle? 180°
- How do you calculate the exterior angle of a triangle? It is equal to the sum of the two opposite interior angles.
- What is the sum of interior angles of a hexagon? 720°
What Examiners Usually Test
- Understanding of angle sums in various polygons
- Ability to calculate individual interior and exterior angles in regular polygons