Interior and Exterior Angles of Triangles

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. It is equal to the sum of the two remote interior angles.

Front

What does the Triangle Sum Theorem state?

Back

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

Front

What is a remote interior angle?

Back

A remote interior angle is an interior angle of a triangle that is not adjacent to a given exterior angle.

Front

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

Back

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

Front

What is the measure of an angle that is supplementary to a 110° angle?

Back

The supplementary angle is 70° (180° - 110° = 70°).

Front

If angle A = 45° and angle B = 55°, what is angle C in triangle ABC?

Back

Angle C is 80° (180° - 45° - 55° = 80°).

Front

What is the definition of an interior angle?

Back

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

Front

How do you find the measure of an unknown angle in a triangle?

Back

To find an unknown angle, subtract the sum of the known angles from 180°.

Front

What is the relationship between corresponding angles when two parallel lines are cut by a transversal?

Back

Corresponding angles are equal when two parallel lines are cut by a transversal.

Front

If angle x is 90° and angle y is 45°, what is the measure of angle z in triangle XYZ?

Back

Angle z is 45° (180° - 90° - 45° = 45°).