Class 6 Maths Chapter 4 Basic Geometrical Ideas Exercise 4.6 pdf notes:-

**Exercise 4.6** Class 6 maths Chapter 4 Pdf Notes:-

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## Ncert Solution for Class 6 Maths Chapter 4 Basic Geometrical Ideas Exercise 4.6 Tips:-

**Circles**

In our environment, you find many things that are round, a wheel, a bangle, a

coin etc. We use the round shape in many ways. It is easier to roll a heavy

steel tube than to drag it.

A circle is a simple closed curve which is not a polygon. It has some very

special properties.

ā¢ Place a bangle or any round shape; trace around to get a circular shape.

ā¢ If you want to make a circular garden, how will you proceed?

Take two sticks and a piece of

rope. Drive one stick into the ground.

This is the centre of the proposed

circle. Form two loops, one at each

end of the rope. Place one loop

around the stick at the centre. Put the

other around the other stick. Keep the sticks vertical to the ground. Keep the

rope taut all the time and trace the path. You get a circle.

Naturally every point on the circle is at equal distance from the centre.

Parts of a circle

Here is a circle with centre C (Fig 4.24)

A, P, B, M are points on the circle. You will see that

CA = CP = CB = CM.

Each of the segments CA , CP , CB, CM is

radius of the circle. The radius is a line segment that

connects the centre to a point on the circle. CP and

CM are radii (plural of āradiusā) such that C, P, M

are in a line. PM is known as diameter of the circle.

Is a diameter double the size of a radius? Yes.

PB is a chord connecting two points on a circle.

Is PM also a chord?

An arc is a portion of circle.

If P and Q are two points you get the arc PQ. We

write it as PQ.

As in the case of any simple closed curve you can

think of the interior and exterior of a circle. A region

in the interior of a circle enclosed by an arc on one

side and a pair of radii on the other two sides is

called a sector.

A region in the interior of a circle enclosed by

a chord and an arc is called a segment of the circle.

Take any circular object. Use a thread and wrap

it around the object once. The length of the thread

is the distance covered to travel around the object

once. What does this length denote?

The distance around a circle is its circumference.

**Do This:-**

Take a circular sheet. Fold it into two halves. Crease

the fold and open up. Do you find that the circular

region is halved by the diameter?

A diameter of a circle divides it into two equal parts;

each part is a semi-circle. A semi-circle is half of a circle,

with the end points of diameter as part of the boundary