Maharashtra State BoardSSC (English Medium) 7th Standard

# Related Angles - Adjacent Angles

## Definition

Adjacent angle: Two angles are adjacent angles if they have a common vertex, a common arm and their non-common arms are on different sides of the common arm.

## Notes

Two angles are adjacent angles if they have
(i) a common vertex,
(ii) a common arm and
(iii) their non-common arms are on different sides of the common arm.

Adjacent angles have a common vertex and a common arm but no common interior points.

• ∠ ABD and ∠ DBC are adjacent angles.
Ray BD is their common arm and point B is their common vertex.
Ray BA and ray BC are noncommon arms.

• Moreover, when two angles are adjacent, then their sum is always equal to the angle formed by the two non- common arms.

∠ ABC = ∠ ABD + ∠ DBC.

## Example

In the given figure, Identify five pairs of adjacent angles.

Five pairs of adjacent angles are (∠AOE, ∠EOC), (∠EOC, ∠COB), (∠AOC, ∠COB), (∠COB, ∠BOD), (∠EOB, ∠BOD).

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