Page 145 - Math Skill - 4

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Let’s Attempt

Example 1: The radius of a circle is 3 cm. Find its diameter.
Challenge
Solution: Radius of the circle = 3 cm I m a part of a line, but not
Since, diameter = 2 × radius its whole, two ends points

= (2 × 3) cm = 6 cm define my role, straight and
Example 2: The diameter of a circle is 10 cm. Find its radius. stand true in geometry,
what am I?
Solution: Diameter of the circle = 10 cm
Since, radius = diameter = 10 cm = 5 cm
2 2

Exercise 10.3

1. Fill in the blanks.
(a) Every point on a circle is at the same distance from the __________ .
(b) Diameter is the __________ chord of the circle.
(c) The length of boundary of a circle is called its _______________.
(d) Diameter of a circle = __________ × radius.
(e) A circle has only __________ centre.
2. In the figures given below, name the following:

(a) P (b) C
M (i) The centre ___ P (i) The centre ___

(ii) A radius ___ (ii) A radius ___
O (iii) A chord ___ A X B (iii) A chord ___

R (iv) A diameter ___ (iv) A diameter ___
N
Q

3. In the figures given below draw the following:

(a) (b)

Radius AX Radius BC

A Chord PQ B Chord XY
Diameter MN Diameter PQ

4. The radii of circles are given. Find the corresponding diameter for each of the following.
(a) 12 cm (b) 14 cm (c) 25 cm (d) 50 cm (e) 100 cm
5. The diameters of circles are given. Find the corresponding radius for each of the following.

(a) 12 cm (b) 10 cm (c) 18 cm (d) 16 cm (e) 20 cm