area of a circular field is154 sq.m. find the time taken byan athlete to complete 2 rounds if the speed is 5 km per hour?

Suppose r be the radius of circular field.
Then area of circular field = πr2 = 154 m2
227r2 = 154 r2 = 722×154r2 = 49r = 49 = 7
Then circumference of circular field = 2πr = 2×227×7 = 44 m
So distance of one round of circular field = circumference of circular field = 44 m
Then distance of 2 round of circular field = 44×2 = 88 m
Speed = 5 km/hr = 5×100060×60 = 2518 m/s
Therefore time taken to cover 2 round of circular field = 882518 = 88×1825 = 63.36 seconds

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