Property.
Section 1
Defining Exterior Angles of a Triangle
An exterior angle of a triangle is formed when one side of the triangle is extended beyond a vertex. The exterior angle and its adjacent interior angle are supplementary, meaning they sum to .
Section 2
Exterior Angle Theorem
An exterior angle is formed when one side of a triangle is extended outward. It forms a linear pair (summing to 180°) with its adjacent interior angle.
The Exterior Angle Theorem states that the measure of an exterior angle equals the sum of the two non-adjacent (remote) interior angles:
Section 3
Polygon Interior Angle Sum Formula
The sum of interior angles of any polygon with sides is given by:
This formula is derived by dividing any polygon into triangles from one vertex.
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Section 1
Defining Exterior Angles of a Triangle
An exterior angle of a triangle is formed when one side of the triangle is extended beyond a vertex. The exterior angle and its adjacent interior angle are supplementary, meaning they sum to .
Section 2
Exterior Angle Theorem
An exterior angle is formed when one side of a triangle is extended outward. It forms a linear pair (summing to 180°) with its adjacent interior angle.
The Exterior Angle Theorem states that the measure of an exterior angle equals the sum of the two non-adjacent (remote) interior angles:
Section 3
Polygon Interior Angle Sum Formula
The sum of interior angles of any polygon with sides is given by:
This formula is derived by dividing any polygon into triangles from one vertex.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter