Question

14. Find the minimum length in cm and correct to
nearest whole number of the thin metal sheet
required to make a hollow and closed cylindrical
box of diameter 20 cm and height 35 cm.
Given that the width of the metal sheet is 1 m.
Also, find the cost of the sheet at the rate of
56 per m.
Find the area of metal sheet required, if 10% of it
is wasted in cutting, overlapping, etc.​

Answer 1

Answer:

Given, a hollow and close cylinder of diameter 20 cm and height 35 cm. width of sheet is 1m and cost of sheet is Rs. 56/m.

Radius =

2

d

=10 cm

So,we have to find total surface area.

Total surface area =2πr(r+h)

=2×

7

22

×10×(10+35)

=2828.57 cm

2

=0.282m

2

Cost of sheet =0.282×56

= Rs.15.8

Length of sheet =

widthofsheet

Areaofsheet

=

1

0.282

=0.28 m =28 cm

Area of metal sheet if 10% is wasted then sheet required = Area of sheet + 10% of sheet

=2828.57+10% of 2828.57

=2828.37+282.8

=3111.57cm