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.

    exAngle Addition Postulateple of Angle Addition Postulate

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’.

Examples of Angle Addition Postulate

    exAngle Addition Postulateple of Angle Addition Postulate
    According to angle addition postulate, m?DAC + m?CAB = m?DAB. So, m?DAB = 35° + 30° = 65°.

Video Examples: Angle Addition Postulate - Geometry Help


Solved Example Clockple on Angle Addition Postulate

Ques:

Find m?CAB. [Given ?DAB = 64° and ?DAC = 53°.]

    exAngle Addition Postulateple of Angle Addition Postulate
    Choices:
    A. 28
    B. 15
    C. 11
    D. 117
    Correct Answer: C

Solution:

    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.]