Page 2 - Lesson Notes

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.

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