Interior and Exterior Angles of Triangles

Front

What is the Triangle Sum Theorem?

Back

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

Front

What is an interior angle of a triangle?

Back

An interior angle of a triangle is an angle formed by two sides of the triangle that is located inside the triangle.

Front

What is an exterior angle of a triangle?

Back

An exterior angle of a triangle is formed by one side of the 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 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 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 the exterior angle of a triangle is 120°, what are the measures of the two non-adjacent interior angles?

Back

The sum of the two non-adjacent interior angles is 120°.

Front

What is the measure of an angle if the other two angles in a triangle are 45° and 45°?

Back

The measure of the third angle is 90° (180° - 45° - 45° = 90°).

Front

What is the measure of angle x if the other two angles are 80° and 30°?

Back

Angle x measures 70° (180° - 80° - 30° = 70°).

Front

What is the sum of the interior angles of a triangle with angles measuring 50°, 60°, and 70°?

Back

The sum is 180° (50° + 60° + 70° = 180°).