Checking and securing understanding of exterior angles
I can find the exterior angle of any regular polygon or deduce the exterior angle of an irregular polygon.
- Year 10
Checking and securing understanding of exterior angles
I can find the exterior angle of any regular polygon or deduce the exterior angle of an irregular polygon.
Lesson details
Key learning points
- The sum of the exterior angles of a polygon can be demonstrated using a point.
- The sum of the exterior angles of a polygon can be proven using interior angles and the angles on a straight line.
- An exterior and interior angles pair are supplementary.
Keywords
Polygon - A polygon is a flat (2D), closed figure made up of straight line segments.
Regular - A regular polygon has sides that are all equal and interior (inside) angles that are all equal.
Interior angle - An interior angle is an angle formed inside a polygon by two of its edges.
Exterior angle - An exterior angle is an angle on the outside of a polygon between an extension of an edge and the adjacent edge.
Common misconception
An exterior angle is equal to 360° - the size of the interior angle because angles around a point sum to 360°.
An exterior angle is an angle on the outside of a polygon between an extension of an edge and the adjacent edge.
Equipment
Licence
Lesson video
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