Exterior Angle of a Triangle

Front

What is the Exterior Angle Theorem?

Back

The Exterior Angle Theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two non-adjacent interior angles.

Front

How many degrees are in a triangle?

Back

A triangle has a total of 180 degrees.

Front

If one angle of a triangle is 60 degrees and another is 80 degrees, what is the measure of the third angle?

Back

The third angle measures 40 degrees.

Front

What is the relationship between an exterior angle and its adjacent interior angle?

Back

The exterior angle is equal to the sum of the two opposite interior angles, and it is supplementary to the adjacent interior angle.

Front

Calculate the measure of angle KLX if angle L is 75 degrees and angle K is 30 degrees.

Back

Angle KLX measures 105 degrees.

Front

If angle SRX is 72 degrees, what is the measure of the exterior angle at vertex R?

Back

The exterior angle at vertex R is 108 degrees (180 - 72).

Front

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

Back

The sum of the exterior angles of a triangle is always 360 degrees.

Front

If angle RPX is 142 degrees, what are the measures of the two non-adjacent interior angles?

Back

The sum of the two non-adjacent interior angles is 38 degrees (180 - 142).

Front

What is the measure of a missing angle in a triangle if the other two angles are 30 degrees and 120 degrees?

Back

The missing angle measures 30 degrees.

Front

Define an exterior angle in the context of a triangle.

Back

An exterior angle is formed by one side of a triangle and the extension of an adjacent side.