Radius of a Circle

Q.

What will be the radius of a circle whose diameter is 20 cm?

1. $10cm$
2. $40cm$
3. $20cm$
4. $60cm$

Q.

Find the radius of a circle of diameter 10 cm.

1. 20 cm
2. 5 cm
3. 10 cm
4. 6 cm

Q.

Find the radius of the circle if the diameter is:

$12cm$

Q.

The distance between the centre and any point on the circle is called the ____.

1. radius

2. diameter

3. circumference

4. arc

Q.

What will be the radius of a circle whose diameter is 36 cm?

1. 11 cm
2. 66 cm
3. 16 cm
4. 18 cm

Q.

If the diameter of a circle is 32 cm, its radius is equal to ___ .

1. 14cm
2. 16cm
3. 32cm
4. 18cm

Q.

Find the radius of a circle if the diameter is $42cm$

Q. Which instrument can be used to measure the radius of a circle?

1. Pencil
2. Protractor
3. Ruler
4. Compass

Q.

What is the diameter of a circle whose radius is $4.2\mathrm{cm}.$

Q.

The number of radii a circle can have is _________________.

Q.

Find the radius of a circle whose diameter is 96 cm.

1. 191 cm
2. 192 cm
3. 48 cm
4. 45 cm

Q. If P is a point(other than the centre) inside a circle and the radius of the circle is r, then the distance between the centre and point P is:

1. less than r
2. greater than r
3. equal to r
4. is zero

Q.

Which of the following is not a radius of the circle with center O?

1. AB

2. OC

3. OA

4. OD

Q.

A circle with center O is shown below. The line segment OA is the ____ of the circle.

1. diameter

2. radius

3. chord

4. segment

Q. If the radii of two concentric circles are 10 cm and 7 cm, then what is the width of the circular ring formed?

1. 10 cm
2. 7 cm
3. 3 cm
4. 5 cm

Q.

If radius of a circle is halved then,

1. the diameter will be tripled

2. the diameter will be same

3. the diameter will be halved

4. the diameter will be doubled

Q. What will be the diameter of a circle whose radius is 15 cm?

1. 7.5 cm
2. 15 cm
3. 30 cm
4. 60 cm

Q.

If the diameter of the circle is $12cm$, find the radius of the circle.

Q.

The radius of inner circle is represented by ________ and of outer circle is represented by _______ .

1. O and OB
2. A and B
3. OA and OB
4. OB and OA

Q.

Find the radius of the circle if the diameter is:

$6cm$

Q. A man moves in a circular park with a radius of 14 cm. Find the diameter of that park.

1. 28 cm
2. 15 cm
3. 40 cm
4. 44 cm

Q. The distance between centre and any point on the circle known as?

1. Radius
2. Centre
3. Area
4. Perimeter

Q. John made a circle with a rope and a nail. Length of the rope is equal to which of the following?

1. Centre
2. Diameter
3. Radius
4. Perimeter

Q. How many radii can a circle have?

1. 1
2. 2
3. 4
4. Infinite

Q. O is the centre of the given circle. Which of the lines OA, OB, OC, OD, BD, or BA are the radii (plural of radius) of the circle? Justify.

Q. While measuring radius of a circle, we look at the value of the mark where the circle intersects the _________ .

1. thread
2. compass
3. scale
4. protractor

Q. There is a circle inside another circle of radius 6 m. What can be the radius of inner circle?

1. 7 m
2. 9 m
3. 8 m
4. 4 m

Q.

If the diameter of a circle is $18.2cm$ , find its radius .

Q.


Guess
• Why did Naina get such a drawing? Discuss.
• Can a circle have more than one centre?

Q.

The diameter of a circle is a line which joins two points on the circle and also passed through the centre of the circle. (In the adjoining figure AB is a diameter of the circle; C is its centre.) Express the diameter of the circle (d) in terms of its radius(r).