11. Calculate total cost of constructing the track

A school play ground is in the shape of a circle with radius 42$m$. Four tracks each of 7$m$ wide has to be constructed inside the play ground for track events. Find out the area of the tracks and the cost of constructing the track at the rate of $₹$50 per $sq$. $m$.

 

 

The area of the $4$ tracks is $m^2$

 

The total cost of constructing the track is $₹$