Triangle Sum & Exterior Angle Theorems

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°.

Front

If one angle of a triangle is 90°, what type of triangle is it?

Back

It is a Right triangle.

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.

Front

What does the Exterior Angle Theorem state?

Back

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

Front

If angle A = 40° and angle B = 60°, what is angle C in triangle ABC?

Back

Angle C = 180° - (40° + 60°) = 80°.

Front

What is the measure of the third angle if two angles of a triangle are 50° and 70°?

Back

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

Front

How do you classify a triangle with angles measuring 30°, 60°, and 90°?

Back

It is classified as a Right triangle.

Front

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

Back

The measure of an exterior angle = measure of the non-adjacent interior angles' sum.

Front

If angle X is an exterior angle and measures 120°, what are the measures of the two non-adjacent interior angles if one is 40°?

Back

The other angle = 120° - 40° = 80°.

Front

What is the relationship between the angles in a triangle?

Back

The sum of the angles in a triangle is always 180°.