# Class 6 Maths Chapter 5 Exercise 5.1 Pdf Notes NCERT Solutions

Class 6 Maths Chapter 5 Understanding Elementary Shapes Exercise 5.1 pdf notes:-

**Exercise 5.1** Class 6 maths Chapter 5 Pdf Notes:-

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## Ncert Solution for Class 6 Maths Chapter 5 Understanding Elementary Shapes Exercise 5.1 Tips:-

**Introduction:-**

All the shapes we see around us are formed using curves or lines. We can see

corners, edges, planes, open curves and closed curves in our surroundings.

We organise them into line segments, angles, triangles, polygons and circles.

We find that they have different sizes and measures. Let us now try to develop

tools to compare their sizes.

5.2 Measuring Line Segments

We have drawn and seen so many line segments. A triangle is made of three,

a quadrilateral of four line segments.

A line segment is a fixed portion of a line. This makes it possible to measure

a line segment. This measure of each line segment is a unique number called

its “length”. We use this idea to compare line segments.

To compare any two line segments, we find a relation between their lengths.

This can be done in several ways.

(i) Comparison by observation:

By just looking at them can you

tell which one is longer?

You can see that AB is

longer.

But you cannot always be

sure about your usual judgment.

For example, look at the

adjoining segments

The difference in lengths between these two may not be obvious. This makes

other ways of comparing necessary.

In this adjacent figure, AB and PQ have the same

lengths. This is not quite obvious.

So, we need better methods of comparing line

segments.

(ii) Comparison by Tracing

To compare AB and CD, we use a tracing paper, trace CD and place the

traced segment on AB.

Can you decide now which one among AB and CD is longer?

The method depends upon the accuracy in tracing the line segment.

Moreover, if you want to compare with another length, you have to trace

another line segment. This is difficult and you cannot trace the lengths

everytime you want to compare them.

(iii) Comparison using Ruler and a Divider

Have you seen or can you recognise all the instruments in your

instrument box? Among other things, you have a ruler and a divider.

The difference in lengths between these two may not be obvious. This makes

other ways of comparing necessary.

In this adjacent figure, AB and PQ have the same

lengths. This is not quite obvious.

So, we need better methods of comparing line

segments.

(ii) Comparison by Tracing

To compare AB and CD, we use a tracing paper, trace CD and place the

traced segment on AB.

Can you decide now which one among AB and CD is longer?

The method depends upon the accuracy in tracing the line segment.

Moreover, if you want to compare with another length, you have to trace

another line segment. This is difficult and you cannot trace the lengths

everytime you want to compare them.

(iii) Comparison using Ruler and a Divider

Have you seen or can you recognise all the instruments in your

instrument box? Among other things, you have a ruler and a divider.