About Lesson
Concept
The sum of the exterior angles of any polygon is always 360 degrees, regardless of the number of sides.
Explanation
1️⃣ Definition of Exterior Angles
- An exterior angle is formed by extending one side of a polygon at a vertex.
- The exterior and interior angles at a vertex are supplementary (sum to 180°).
2️⃣ Full Rotation Around the Polygon
- Imagine walking around the polygon and turning at each vertex to follow the exterior angles.
- By the time you complete one full circuit, the total turn is 360°.
3️⃣ Mathematical Proof
- A convex polygon with n sides has interior angles summing to:
180(n−2)degrees - Since each exterior angle is:
Exterior Angle=180°−Interior Angle - Summing all exterior angles across all vertices results in:
360°
Key Takeaways
✅ The sum of exterior angles of any polygon (regular or irregular) is always 360°.
✅ This rule applies to all polygons, including triangles, quadrilaterals, pentagons, etc.
✅ Each exterior angle of a regular polygon is 360°/n, where n is the number of sides.