Geo Ch 1.8 Exterior <, Triangle Sum, Vertical angles

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 one angle of a triangle is 90 degrees, what are the measures of the other two angles?

Back

The other two angles must sum to 90 degrees, as the total must equal 180 degrees.

Front

What are vertical angles?

Back

Vertical angles are the angles opposite each other when two lines intersect. They are always equal.

Front

If two angles are vertical angles and one measures 35 degrees, what is the measure of the other angle?

Back

The other angle also measures 35 degrees, as vertical angles are equal.

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 exterior angle of a triangle measures 120 degrees, and one of the non-adjacent interior angles measures 50 degrees, what is the measure of the other non-adjacent interior angle?

Back

The other non-adjacent interior angle measures 70 degrees, since 120 = 50 + x.

Front

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

Back

To find an unknown angle, subtract the sum of the known angles from 180 degrees.

Front

What is the relationship between complementary angles?

Back

Complementary angles are two angles whose measures add up to 90 degrees.

Front

What is the relationship between supplementary angles?

Back

Supplementary angles are two angles whose measures add up to 180 degrees.

Front

If angle A is 45 degrees and angle B is supplementary to angle A, what is the measure of angle B?

Back

Angle B measures 135 degrees, since 180 - 45 = 135.