Interior and Exterior Angles of Triangles

Front

What is the Triangle Sum Theorem?

Back

The Triangle Sum Theorem states that the sum of the interior angles of a triangle is always 180°.

Front

If one angle of a triangle is 70° and another is 60°, what is the measure of the third angle?

Back

The third angle is 50° (180° - 70° - 60° = 50°).

Front

What is an interior angle of a triangle?

Back

An interior angle is an angle formed inside a triangle by two sides.

Front

What is an exterior angle of a triangle?

Back

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

Front

How do you calculate an exterior angle of a triangle?

Back

An exterior angle is equal to the sum of the two opposite interior angles.

Front

If one angle of a triangle is 40° and the exterior angle is 120°, what is the measure of the other interior angle?

Back

The other interior angle is 60° (120° - 40° = 80°, and 180° - 80° = 100°).

Front

What is the relationship between interior and exterior angles?

Back

The exterior angle is equal to the sum of the two non-adjacent interior angles.

Front

If a triangle has angles measuring 30° and 50°, what is the measure of the third angle?

Back

The third angle measures 100° (180° - 30° - 50° = 100°).

Front

What is the measure of an angle if the exterior angle is 150°?

Back

The interior angle is 30° (150° - 120° = 30°).

Front

What is the measure of angle x if the interior angles are 45° and 75°?

Back

Angle x measures 60° (180° - 45° - 75° = 60°).