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.

Tags

CCSS.8.G.A.5

Front

If one interior angle of a triangle is 30 degrees and another is 50 degrees, what is the measure of the exterior angle?

Back

The exterior angle is 30 + 50 = 80 degrees.

Tags

CCSS.8.G.A.5

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, not the adjacent one.

Tags

CCSS.8.G.A.5

Front

How do you find the measure of an unknown angle using the Exterior Angle Theorem?

Back

To find an unknown angle, add the measures of the two non-adjacent interior angles.

Tags

CCSS.8.G.A.5

Front

If the exterior angle is 120 degrees, what are the possible measures of the two non-adjacent interior angles?

Back

The sum of the two non-adjacent interior angles must equal 120 degrees.

Tags

CCSS.8.G.A.5

Front

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

Back

The sum of the interior angles of a triangle is always 180 degrees.

Tags

CCSS.8.G.A.5

Front

If one angle of a triangle is 70 degrees and another is 40 degrees, what is the measure of the exterior angle at the vertex of the 70-degree angle?

Back

The exterior angle is 40 + (180 - 70 - 40) = 70 degrees.

Tags

CCSS.8.G.A.5

Front

Can the Exterior Angle Theorem be applied to any polygon?

Back

No, the Exterior Angle Theorem specifically applies to triangles.

Tags

CCSS.8.G.A.5

Front

What is an example of using the Exterior Angle Theorem in a problem?

Back

If angle A = 50 degrees and angle B = 60 degrees in triangle ABC, then the exterior angle at C is 50 + 60 = 110 degrees.

Tags

CCSS.8.G.A.5

Front

What is the formula for calculating an exterior angle in a triangle?

Back

Exterior Angle = Interior Angle 1 + Interior Angle 2.

Tags

CCSS.8.G.A.5