Find the circumference of the circles with the following radius:


(a) 14 cm (b) 28 mm (c) 21 cm


(a) It is given in the question that,


 


Radius of the circle = 14 cm


 


We know that,


 


Circumference of the circle = 2πr


= 2 × π × 14


= 2 × (22/7) × 14


= 2 × (22/7) × 2


= 88 cm


 


(b) It is given in the question that,


 


Radius of the circle = 28 mm


 


We know that,


Circumference of the circle = 2πr


= 2 × π × 28mm


= 2 × (22/7) × 28mm


= 2 × (22) × 4


=176 mm


 


(c) It is given in the question that,


 


Radius of the circle = 21 cm


 


We know that,


 


Circumference of the circle = 2πr


= 2 × π × 21 cm


= 2 × (22/7) × 21 cm


= 2 × (22) × 3 cm


= 132 cm

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