Angle Addition Postulate

Front

What is the Angle Addition Postulate?

Back

The Angle Addition Postulate states that if point D is in the interior of angle ABC, then m∠ABD + m∠DBC = m∠ABC.

Front

If m∠ECD = 122° and m∠BCE = 36°, what is m∠BCD?

Back

m∠BCD = 158° (using the Angle Addition Postulate).

Front

If m∠VMN = x + 101 and m∠LMV = x + 36, and m∠LMN = 129°, find m∠LMV.

Back

m∠LMV = 32°.

Front

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

Back

Use the fact that the sum of the angles in a triangle is always 180°.

Front

If m∠TSP = 54° and m∠TSR = 138°, what is m∠PSR?

Back

m∠PSR = 84° (using the Angle Addition Postulate).

Front

What is the sum of angles in a triangle?

Back

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

Front

If angle JHG measures 161°, what can you say about angles GHK and KHJ if they are complementary?

Back

m∠GHK + m∠KHJ = 180°.

Front

What is a complementary angle?

Back

Two angles are complementary if the sum of their measures is 90°.

Front

What is a supplementary angle?

Back

Two angles are supplementary if the sum of their measures is 180°.

Front

If m∠ABC = 105°, what is the measure of its supplementary angle?

Back

The supplementary angle is 75° (180° - 105°).