Exterior Angle Theorem Triangles

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

If one interior angle of a triangle is 30° and another is 70°, what is the measure of the exterior angle?

Back

The exterior angle is 100° (30° + 70°).

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.

Front

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

Back

Add the measures of the two non-adjacent interior angles to find the measure of the exterior angle.

Front

If the exterior angle is 120°, 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°.

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°.

Front

If one angle of a triangle is 90°, what type of triangle is it?

Back

It is a right triangle.

Front

In a triangle, if one angle measures 45°, what is the maximum measure of the exterior angle?

Back

The maximum measure of the exterior angle can be 135° (45° + 90°).

Front

What is the formula to calculate the measure of an exterior angle?

Back

Exterior Angle = Interior Angle 1 + Interior Angle 2.

Front

If the exterior angle is 94°, what are the measures of the two non-adjacent interior angles if one is 49°?

Back

The other non-adjacent interior angle must be 45° (94° - 49°).