Answers

2016-04-21T20:47:07+08:00
Π/6    =   30°   which is equal     to 1/12   part of a circle
    thus      1/12  πr²   =  64 m²     /  area of circle =  πr²
              r²  = ( 64*12)/π   =   224.58
              r  =   √244.58   ≈   15.63m
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