Exterior Angles of Polygons
The Exterior Angle is the angle between any side of a shape,
and a line extended from the next side.
Note: when you add up the Interior Angle and Exterior Angle you get a straight line, 180°. (See Supplementary Angles)
Polygons
A Polygon is any flat shape with straight sides
The Exterior Angles of a Polygon add up to 360° |
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In other words the exterior angles add up to one full revolution (Exercise: try this with a square, then with some interesting polygon you invent yourself.) Note: This rule only works for simple polygons |
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| Here is another way to think about it: Each lines changes direction until you eventually get back to the start: |
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