Video: The Sum of the Exterior Angles of a Triangle

What is the sum of the measures of the exterior angles of a triangle?

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Video Transcript

What is the sum of the measures of the exterior angles of a triangle?

Well, the sum of the exterior angles of any polygon are equal to 360 degrees. If we consider an equilateral triangle where all the interior angles are equal to 60 degrees, then it is clear that the three exterior angles would all be equal to 180 degrees as 180 minus 60 is equal to 120.

Angles on a straight line equal 180 degrees. Adding the three exterior angles or multiplying 120 by three gives us 360 degrees. Therefore, the sum of the measures of the exterior angles of an equilateral triangle are 360 degrees.

This fact is also true for any triangle. And as mentioned at the start of the question is also true for any polygon. The sum of the exterior angles of any polygon equal 360 degrees.

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