Question

find the circumference of each circle. take π =22/7 in question 1,
(iii) radius = 2.1 m (iv) diameter
= 9.8 m​

Answer 1

Answer:

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Circle

Important Formulae

Diameter of a circle is usually denoted by ‘D’.

Radius of a circle is denoted by ‘r’, thus, diameter = 2r

Circumference of circle = 2 π r, where r is the radius of circle

Area of circle = 2 π r2

Question 1: Find the circumference of the circles with the following radius: (a) 14 cm (b) 28 mm (c) 21 cm

Solution: (a) Given, radius, r = 14 cm

We know that circumference

=

2

π

r

=

2

×

22

7

×

14

=

2

×

22

×

2

=

88

cm

(b) Given, radius, r = 28 mm,

We know that circumference

=

2

π

r

=

2

×

22

7

×

28

=

2

×

22

×

4

=

176

mm

(c) Given, radius, r = 21 cm

We know that circumference

=

2

π

r

=

2

×

22

7

×

21

=

2

×

22

×

3

=

132

Answer 2

Answer:

1) circumference of of a circle whose radius is =2.1 m

circumference of circle=

2 x 22/7 x 2.1 = 13.2

Step-by-step explanation:

2) radius = 4.9

2 x 22/7 x 4.9 = 3.8

I hope you understand my answer.