Question

Road 3.5 M wide surrounds a circular plot whose circumference is 44 M find the cost of paving the road at peace 20 per metre square take Pi is equal to 22 by 7

Answer 1

circumference of circular plot = 2 ii r
it is  given = 44 M
                  2 * 22 /7 * r = 44
                  r = 44 * 7 /2* 22
                  r = 7 M
now area of plot = 22/7 * 7 * 7 
                           = 154 sq. M 
radius of plot including path = 7 + 3.5
                                            = 10.5 M
 area of path including path = 22/7 * 10.5 * 10.5
                                            =346.5 sq M
area of path = area of plot including path - area of plot 
                     = 346.5 - 154
                     = 192.5 sq.M
    cost for paving the road = Rs. 20 per sq. m
       cost for paving 192.5 sq. m road = 20 * 192.5
                                                            = Rs. 3850.