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Types of                Angles can be
        angles                    classified on the
                                  basis of their
                                  measurements as.
                                Acute Angle , Right
                                  Angles ,
                                  Obtuse Angles ,
                                  Straight Angles,
                                   Reflex Angles,
                                  Complete Angles



        Interior and            The shaded portion
        Exterior of an            between the arms
        angle                     BA and BC of the
                                  angle ABC can be
                                  extended
                                  indefinitely.
                                This portion is called
                                  the interior of the
                                  angle. X is a point in
                                  the interior of the
                                  angle.
                                The point Y lies in
                                  the exterior of the
                                  angle.
                                The point Z lies on
                                  the angle.
        Triangles               A triangle is a
                                  simple closed curve
                                  or polygon which is
                                  formed by three line-
                                  segments.
                                The basic elements
                                  of the triangle are 3
                                  sides, 3 angles, and
                                  3 vertices.
                                The 3 angles always
                                  add to 180°.
                                When naming the
                                  triangle, we can
                                  begin with any
                                  vertex. Then keep
                                  the letters in order
                                  as you go around
                                  the polygon.
                                `triangle ABC`, or
                                  `triangle BCA`,
                                  `triangle CAB`


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