Angle Addition Postulate
Definition of Angle Addition Postulate
- Angle Addition Postulate states that if a point S lies in the interior of ?PQR, then ?PQS + ?SQR = ?PQR.
More about Angle Addition Postulate
- If the sum of the two angles measure up to 90°, then the angles are called to be ‘complementary angles’.
- If the sum of the two angles measure up to 180°, then the angles are called to be ‘supplementary angles’.
- The angles sharing a common side are called as ‘adjacent angles’.
Example of Angle Addition Postulate
- According to angle addition postulate, m?DAC + m?CAB = m?DAB. So, m?DAB = 35° + 30° = 65°.
Solved Example on Angle Addition Postulate
Find m?CAB. [Given ?DAB = 64° and ?DAC = 53°.]
Correct Answer: C
Step 1: m?DAC + m?CAB = m?DAB [Angle Addition Postulate.]
Step 2: ? m?CAB = m?DAB - m?DAC
Step 3: ? m?CAB = 64 – 53 [Substitute.]
Step 4: m?CAB = 11 [Add.]