Answers

2014-07-18T22:57:54+08:00
Formula for length of arc of a circle =        S =  rθ   where θ is in radians
  S = length of arc;        r = radius    &  θ = angle in radians
               180⁰ =    π  radian
                   80⁰ =    π/180 * 80  =    4/9 π
THUS
               S =    rθ =    180* 4/9π  =  80π meter
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