Page 2: Triangles, Quadrilaterals, and Polygons
This page explores triangle properties, polygon classifications, and methods for calculating interior angles in various shapes.
Definition: A polygon is a 2D shape with straight edges only, and it's considered regular when all sides and angles are equal.
Highlight: Triangle interior angles always sum to 180°, while quadrilateral interior angles sum to 360°.
Example: Triangle types include:
- Right-angled triangles (one 90° angle)
- Isosceles triangles (two equal sides and angles)
- Equilateral triangles (all sides and angles equal)
- Scalene triangles (all sides and angles different)
Vocabulary: Polygon names are based on their number of sides:
- Pentagon (5 sides)
- Hexagon (6 sides)
- Heptagon/Septagon (7 sides)
- Octagon (8 sides)
- Nonagon (9 sides)
- Decagon (10 sides)





