Interior and Exterior Angles of Triangles

Front

What is the sum of the interior angles of a triangle?

Back

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.

Front

What is the relationship between an exterior angle and the two opposite interior angles?

Back

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

Front

If one angle of a triangle is 50 degrees and another is 60 degrees, what is the measure of the third angle?

Back

The third angle measures 70 degrees (180 - 50 - 60 = 70).

Front

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

Back

Each angle in an equilateral triangle measures 60 degrees.

Front

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

Back

Subtract the sum of the known angles from 180 degrees.

Front

What is the formula for finding the measure of an exterior angle?

Back

The measure of an exterior angle is equal to the sum of the two opposite interior angles.

Front

If angle A is 40 degrees and angle B is 70 degrees, what is angle C in triangle ABC?

Back

Angle C is 70 degrees (180 - 40 - 70 = 70).

Front

What is the measure of an angle that is supplementary to a 120-degree angle?

Back

The supplementary angle measures 60 degrees (180 - 120 = 60).

Front

What is the measure of an angle that is complementary to a 30-degree angle?

Back

The complementary angle measures 60 degrees (90 - 30 = 60).