A square water tank has its side equal to 40 m. There are four semi-circular grassy plots all round it. Find the cost of turfing the plot at Rs. 1.25 per square metre (Take π = 3.14).
Solution
It is given that the side of square . `a=40 m`
Since four semicircular grassy plots rounds a square water tank. Then, diameter of semicircular plot is`2r=a`.
So, the radius of semicircle
`r=a/2`
`=40/2`
`20 m`
Area of semicirular plot=`1/2 pir^2`
`= 1/2xx3.14xx20xx20`
`=628 m^2`
Now, the total area of plot is sum of area of four semicircular plots.
`"Total Area of plot"=4xx "Area of semicircle"`
`=4xx628 m^2`
` = 2512 m^2`
Since, The cost of turding the plot per squre meter=`Rs.1.25`
So, The cost turfing 2512 square meter plot= `Rs1.25xx2512`
`= Rs 3140`
