Answers

2015-11-26T21:14:34+08:00
If you think on circumference of a circle. 

C = d * pi 

pi = 22 / 7 


C = d * pi 

C = 2.1 * ( 22 / 7 ) = 2.1 * 22 / 7 = 46.2 / 7 = 6.6 
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