Exterior Angle Theorem

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

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

Back

180 degrees.

Front

If one angle of a triangle is 50 degrees and another is 60 degrees, what is the measure of the exterior angle adjacent to the 60-degree angle?

Back

70 degrees (50 + 60 = 110 degrees, so the exterior angle is 180 - 110 = 70 degrees).

Front

In triangle ABC, if angle A = 40 degrees and angle B = 70 degrees, what is the measure of angle C?

Back

70 degrees (180 - 40 - 70 = 70 degrees).

Front

Which angles can be added together to equal an exterior angle?

Back

The two non-adjacent interior angles.

Front

If angle A = 30 degrees and angle B = 50 degrees, what is the measure of the exterior angle at vertex C?

Back

80 degrees (30 + 50 = 80 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 non-adjacent interior angles.

Front

If angle D is an exterior angle and measures 120 degrees, what is the sum of the two non-adjacent interior angles?

Back

120 degrees.

Front

In triangle XYZ, if angle X = 45 degrees and angle Y = 55 degrees, what is the measure of angle Z?

Back

80 degrees (180 - 45 - 55 = 80 degrees).

Front

What is the measure of an exterior angle if the two non-adjacent interior angles are 30 degrees and 50 degrees?

Back

80 degrees (30 + 50 = 80 degrees).