2-3: Triangle Sum & Exterior Angles

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 degrees.

Front

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

Front

What are remote interior angles?

Back

Remote interior angles are the two angles inside a triangle that are not adjacent to a given exterior angle.

Front

If one angle of a triangle is 90 degrees, what is the sum of the other two angles?

Back

The sum of the other two angles is 90 degrees, since the total must equal 180 degrees.

Front

What is the measure of the missing angle if two angles of a triangle are 50° and 60°?

Back

The missing angle is 70°, calculated as 180° - (50° + 60°).

Front

How do you find the measure of an exterior angle?

Back

To find the measure of an exterior angle, add the measures of the two remote interior angles.

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 A is 67° and angle B is an exterior angle, what is the measure of angle B if angle C is 54°?

Back

Angle B measures 121°, calculated as 67° + 54°.

Front

What is the value of x if angle A is 38° and angle B is 90° in a right triangle?

Back

x = 52°, calculated as 180° - (38° + 90°).

Front

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

Back

The supplementary angle measures 70°, calculated as 180° - 110°.