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 always 180°.

Front

If one angle of a triangle is 90°, what can you say about the other two angles?

Back

The other two angles must be acute angles that add up to 90°.

Front

What is the measure of each angle in an equilateral triangle?

Back

Each angle in an equilateral triangle measures 60°.

Front

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

Back

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

Front

What is the relationship between interior and exterior angles of a triangle?

Back

Each exterior angle of a triangle is equal to the sum of the two opposite interior angles.

Front

Can a triangle have two obtuse angles? Why or why not?

Back

No, a triangle cannot have two obtuse angles because the sum of the angles would exceed 180°.

Front

What is the measure of the third angle if two angles of a triangle are 45° and 55°?

Back

The third angle measures 80° (180° - 45° - 55° = 80°).

Front

If a triangle has angles measuring 70° and 40°, what is the measure of the third angle?

Back

The third angle measures 70° (180° - 70° - 40° = 70°).

Front

What set of angles can form a triangle? 45°, 65°, 70° or 150°, 110°, 100°?

Back

The set 45°, 65°, 70° can form a triangle because their sum is 180°.

Front

What is the measure of an angle if its supplement is 120°?

Back

The angle measures 60° (180° - 120° = 60°).