PW Class 6 Mathematics Chapter 2 Lines and Angles Notes

A point, line, line segment, and ray may look closely connected in geometry, but each has a different meaning. As you move further into the chapter, these basic elements lead to angles and the different ways in which angles can be identified and related.

The Lines and Angles Class 6 Notes by PW cover these concepts through definitions, examples, and visual representations. You can revise the different types of angles, understand complementary, supplementary, and adjacent angles, identify a linear pair, and see how a protractor is used for measuring angles.

What Are Points, Lines, Line Segments, and Rays?

These geometrical elements differ mainly in their dimensions or endpoints. The table below makes the distinction clear.

A line extends in both directions, a line segment has two endpoints, and a ray begins at one endpoint and continues endlessly in the other direction. 

What Is an Angle?

When two lines or line segments intersect, they form corners called angles. An angle shows the space formed between the two intersecting lines or line segments.

An angle can be named using three letters, with the middle letter representing the point where the angle is formed. For example, angles can be written as ∠ABC, ∠XOY, ∠ZOW, ∠YOZ, or ∠XOZ.

• Different Types of Angles

There are a total of six types of angles.

• Complementary and Supplementary Angles

Complementary and supplementary angles can be distinguished by the sum of the two angles.

The difference is therefore in the total: complementary angles add up to 90°, whereas supplementary angles add up to 180°.

• Adjacent Angles

Adjacent angles are a pair of angles placed next to each other.

They have:

• A common vertex

• A common arm

• Non-common arms that can be on either side of the common arm

Adjacent angles can be distinguished by their position. They share a common vertex and a common arm, while their non-common arms lie on either side of the common arm.

• Linear Pair

A linear pair is a pair of adjacent angles whose non-common arms make a single line, which means they are opposite rays.

Example:

120° + 60° = 180°

The same pair has three characteristics:

• It is adjacent because the angles have one common arm.

• It is supplementary because the two angles add up to 180°.

• It is a linear pair because the sum is 180° and the non-common arms are opposite rays.

How Are Angles Measured Using a Protractor?

The degree measure of an angle can be measured using a protractor. A protractor is also used to draw angles.

It can be semicircular or circular in shape and is marked with degree measurements.

How Do PW Class 6 Maths Notes Help with Lines and Angles?

Some concepts in this chapter are closely related, so the PW Lines and Angles Class 6 Notes can be used to compare them rather than revising each definition in isolation.

• Line, line segment, and ray: Compare them according to the number of endpoints shown in their diagrams.

• Types of angles: Use the visual representations to distinguish acute, right, straight, obtuse, reflex, and complete angles.

• Complementary and supplementary angles: Compare their sums; 90° for complementary angles and 180° for supplementary angles.

• Adjacent angles and linear pairs: Look at the common arm, common vertex, non-common arms, and the sum of the angles to understand how they are related.

• Protractors: Revisit the difference between semicircular and circular protractors and their degree measurements.

Complete PW Resources for Class 6 Maths Preparation

Once you are familiar with the concepts in the Lines and Angles Class 6 Notes by PW, these related resources can be used for further study and question practice.

Lines and angles cover several concepts that are easier to distinguish when you compare their definitions, diagrams, and relationships. The PW Lines and Angles Class 6 Notes keep these ideas together, helping you revisit geometrical elements, angle types, related angles, linear pairs, and protractors during chapter revision.