MATHEMATICS
Chapter 6: Lines and Angles
, LINES AND ANGLES
06
Lines and Angles
Introduction to line and the terms related to it
• A line is a breadthless length which has no end point. Here, AB is a line and it is
denoted by ⃡AB.
• A line segment is a part of a line which has two end points. Here, AB is a line
segment and it is denoted by AB.
• A ray is a part of a line which has only one end point. Here, AB is a ray and it is
denoted by AB.
Collinear/Non-collinear points
• Three or more points which lie on the same line are called collinear points.
• Three or more points which do not lie on a straight line are called non-collinear
points.
Introduction to Angle
• An angle is formed when two rays originate from the same end point.
• The rays making an angle are called the arms of the angle.
• The end point from where the two rays originate to form an angle is called the
vertex of the angle.
Types of angles:
(1)
, LINES AND ANGLES
06
Pair of Angles
• Two angles whose sum is 90° are called complementary angles.
• Two angles whose sum is 180° are called supplementary angles.
Intersecting and non-intersecting lines
Adjacent angles
Two angles are adjacent, if they have a common vertex, a common arm and their non–
common arms are on different sides of the common arm.
In the figure, ∠ABD and ∠DBC are adjacent angles.
Linear pair of angles
(2)
Chapter 6: Lines and Angles
, LINES AND ANGLES
06
Lines and Angles
Introduction to line and the terms related to it
• A line is a breadthless length which has no end point. Here, AB is a line and it is
denoted by ⃡AB.
• A line segment is a part of a line which has two end points. Here, AB is a line
segment and it is denoted by AB.
• A ray is a part of a line which has only one end point. Here, AB is a ray and it is
denoted by AB.
Collinear/Non-collinear points
• Three or more points which lie on the same line are called collinear points.
• Three or more points which do not lie on a straight line are called non-collinear
points.
Introduction to Angle
• An angle is formed when two rays originate from the same end point.
• The rays making an angle are called the arms of the angle.
• The end point from where the two rays originate to form an angle is called the
vertex of the angle.
Types of angles:
(1)
, LINES AND ANGLES
06
Pair of Angles
• Two angles whose sum is 90° are called complementary angles.
• Two angles whose sum is 180° are called supplementary angles.
Intersecting and non-intersecting lines
Adjacent angles
Two angles are adjacent, if they have a common vertex, a common arm and their non–
common arms are on different sides of the common arm.
In the figure, ∠ABD and ∠DBC are adjacent angles.
Linear pair of angles
(2)
