Theorem: An exterior angle of a triangle is equal to the sum of the opposite interior angles. … The exterior angle at B is always equal to the opposite interior angles at A and C. Although only one exterior angle is illustrated above, this theorem is true for any of the three exterior angles.
MATH335 Content – Exterior Angle Theorem
Triangle Exterior Angle Theorem (Numerical Example)
Frequently Asked Questions
What is true about the measure of exterior angle of a triangle?
The measure of an exterior angle of a triangle is equal to the sum of the measures of the two non-adjacent interior angles of the triangle.
How do you prove the exterior angle theorem?
0:003:53Proof: The Exterior Angles Theorem - YouTubeYouTubeStart of suggested clipEnd of suggested clipWelcome to a proof of the exterior angle theorem the exterior angle theorem states the sum of theMoreWelcome to a proof of the exterior angle theorem the exterior angle theorem states the sum of the remote interior angles is equal to the non adjacent exterior angle.
How do you calculate the angles of a triangle?
Calculating the Angles. We can use equations to represent the measures of the angles described above. One equation might tell us the sum of the angles of the triangle. For example, x + y + z = 180. We know this is true, because the sum of the angles inside a triangle is always 180 degrees.