An angle is made up of two rays starting from a common end point.
Here, angle is formed by the rays and .
The name of the angle is ∠AOB or ∠BOA keeping the vertex in the
The interior of the angle is bounded by the arms of an angle.
The exterior of the angle is the region that lies outside the angle.
Example: Name the angles in the figure:
The four angles in the given figure are
∠DAB, ∠ABC, ∠BCD and ∠CDA
Example: In the given diagram, name the point(s)
a) In the interior of ∠DOE
b) In the exterior of ∠EOF
c) On ∠EOF
a)Point in the interior of ∠DOE is A.
b) Points in the exterior of ∠EOF is C, A and D.
c) Points on ∠EOF is E, B, O and F.
Example: Draw rough diagrams of two angles such that they have
a) One point in common.
b) Two points in common.
c) Three points in common.
d) Four points in common.
e) One ray in common.
a) One point in common
∠AOB and ∠COD have only one point in common, i.e. O
b) Two points in common
∠BOC and ∠COD have two points in common, i.e. O and C
c) Three points in common
∠BOC and ∠COD have three points in common, i.e. O, E and C.
d) Four points in common
∠BOC and ∠COD have four points in common, i.e. O, C, E and F.