Exterior Angle Theorem

Front

What is the Exterior Angle Theorem?

Back

The Exterior Angle Theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two non-adjacent interior angles.

Front

If angle d is an exterior angle, which angles can be added to find its measure?

Back

Angle a and Angle b, which are the two non-adjacent interior angles.

Front

How do you find the measure of an exterior angle if you know the measures of the two non-adjacent interior angles?

Back

Add the measures of the two non-adjacent interior angles together.

Front

What is the relationship between an exterior angle and its adjacent interior angle?

Back

The exterior angle is equal to the sum of the two opposite interior angles, not the adjacent one.

Front

If angle a = 67° and angle b = 79°, what is the measure of angle d?

Back

Angle d = angle a + angle b = 67° + 79° = 146°.

Front

What is the formula to calculate the measure of an exterior angle?

Back

The formula is: m∠d = m∠a + m∠b, where m∠d is the exterior angle and m∠a and m∠b are the non-adjacent interior angles.

Front

If m∠B = 67°, what is the measure of the exterior angle formed at vertex B?

Back

To find the exterior angle, you need the measures of the other two interior angles.

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°.

Front

If one interior angle of a triangle is 38°, what is the maximum possible measure of the other two angles?

Back

The maximum possible measure of the other two angles combined is 142° (since 180° - 38° = 142°).

Front

How can you determine if a triangle is valid based on its angles?

Back

A triangle is valid if the sum of its interior angles is exactly 180°.