3.3 Triangle Angle Sum Theorem

Front

What does the Triangle Angle Sum Theorem state?

Back

The Triangle Angle 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 can you say about the other two angles?

Back

The other two angles must sum to 90° because the total must equal 180°.

Front

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

Back

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

Front

If angle A = 45° and angle B = 45°, what is angle C in triangle ABC?

Back

Angle C = 90° (180° - 45° - 45° = 90°).

Front

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

Back

Each angle in an equilateral triangle measures 60°.

Front

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

Back

Subtract the sum of the known angles from 180°.

Front

If angle A = 36° and angle B = 64°, what is angle C?

Back

Angle C = 80° (180° - 36° - 64° = 80°).

Front

What is the relationship between the angles in a right triangle?

Back

In a right triangle, one angle is 90°, and the other two angles must sum to 90°.

Front

If angle A = 30° and angle B = 30°, what is angle C in triangle ABC?

Back

Angle C = 120° (180° - 30° - 30° = 120°).

Front

What is the sum of the angles in a triangle?

Back

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