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(c) All diameters of a circle are of equal length.

(d) A circle has only one diameter.

(e) A circle has only one centre.

(f) The radius is half of the diameter of a circle.

2. Look at the given circles. Name the centre, radius and diameter.

(a) B (b)
A

O B O A

C

3. Which of the line segments shown in the given circle is its:

(a) radius? (b) diameter?
A C

O
O B A B

C D P

4. Draw a circle with the given radius.

(a) 4 cm (b) 3.5 cm

(c) 5.2 cm (d) 6.4 cm

5. Find the diameter of the circle with the given radius.

(a) 10 cm (b) 13 cm (c) 9 cm (d) 5 cm (e) 7 m

6. Find the radius of the circle with the given diameter.

(a) 12 cm (b) 40 cm (c) 26 cm (d) 64 cm (e) 80 cm

soLiD sHaPes

We know that a cube, cuboid, sphere, cylinder, cone, etc. are solids. Solids are called

3-dimensional (3D) shapes as these have length, width and height (depth).

The surface of solid shape is called a face.
The line where two faces meet is called an edge.

The point where the edges meet is called a corner or vertex.

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