Triangle Sum Theorem and Exterior Angle Theorem

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

If two angles in a triangle are 45° and 75°, what is the measure of the third angle?

Back

60° (Using the Triangle Sum Theorem: 180° - (45° + 75°) = 60°).

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 one angle of a triangle is 51° and another is 47°, what is the value of x if x is the third angle?

Back

x = 180° - (51° + 47°) = 82°.

Front

What equation would solve for x if the angles in a triangle are x, 51°, and 47°?

Back

x + 51 + 47 = 180.

Front

What is the value of k if the angles in a triangle are k, 22°, and 38°?

Back

k = 180° - (22° + 38°) = 120°.

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 non-adjacent interior angles.

Front

If an exterior angle measures 130°, what are the measures of the two non-adjacent interior angles if one is 50°?

Back

The other angle is 130° - 50° = 80°.

Front

What is the relationship between the angles in a triangle and the exterior angle?

Back

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

Front

If the angles in a triangle are 30°, 60°, and x°, what is the value of x?

Back

x = 180° - (30° + 60°) = 90°.