Question

find the minimum length in CM and correct to nearest whole no of thin metal sheet required to make a hollow cylindrical box of diameter 20cm and height 35cm.given that the width of the sheet is 1m
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Answer 1

Answer:

let length of metal sheet be l and breadth be b

Breadth     b = 1m = 100 Cm

radius of cylindrical box r = 10 Cm

and      Height               h = 35 Cm

Thus area of of closed cylindrical box = 2pi r h + 2 pi r^2

                                                            = 2*3.14*10*35 + 2*3.14*100

                                                            = 2198 + 628

                                                           = 2826 Cm sq

     Thus

Area of box = area of Sheet

                                   2826 = l * b

                                      l = 2826/100

                                      l = 28.26 Cm

Thus length of sheet is 28.26 Cm

Cost of 1 msq of sheet = 56 Rs

Cost of 10000Cm Sq = 56/10000 Rs

Cost of 2826 Cmsq = 56 * 0.2826 Rs

                               = 15.8256 Rs

Thus total cost of sheet is 15.8256 Rs

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