Polygons
Properties of regular and irregular polygons, interior and exterior angles
lessons (5)
Introduction to Polygons
Learn what polygons are and how to identify them by their sides and vertices.
Diagonals of Polygons
Learn what diagonals are, how to draw them, and discover the formula to count them in any polygon.
Classifying Polygons
Learn to identify and classify polygons by their number of sides and angles.
Polygon Angle Sum Formula
Learn the formula to calculate the sum of interior angles in any polygon.
Exterior Angles of Polygons
Learn what exterior angles are, how to find them, and discover why they always sum to 360 degrees.
Polygons are closed figures formed by straight line segments. From triangles to regular octagons, understanding polygon properties including angle sums, symmetry, and classifications is essential for geometry and real-world applications in design, architecture, and art.
What Students Will Learn
- Classify polygons by number of sides
- Calculate interior and exterior angle sums
- Identify regular and irregular polygons
- Find measures of angles in polygons
- Apply polygon properties to solve problems
Frequently Asked Questions
How do I find the sum of interior angles?
Use the formula $(n-2) \times 180°$ where n is the number of sides. A pentagon (5 sides) has $(5-2) \times 180° = 540°$.
What makes a polygon regular?
A regular polygon has all sides equal length AND all angles equal measure. A square is regular; a rectangle is not.
What is the sum of exterior angles?
For any convex polygon, the sum of exterior angles is always 360°, regardless of the number of sides.