A solid toy is in the form of a cylinder with hemispherical ends. If the entire length of the solid is 108 cm and the diameter of the hemispherical ends is 36 cm, find the cost of polishing the surface of the solid at the rate of 7 paise per sq. cm. (Use = 22/7)

Asked by Topperlearning User | 18th Feb, 2014, 09:26: AM

Expert Answer:

Diameter of the hemispherical ends = 36 cm

Thus, AD = BC = 36 cm

And, radius = 36/2 = 18 cm

Thus, OM = O'N = 18 cm

Now, height of the cylinder = OO' = MN - MO - NO' = 108 cm - 18 cm - 18 cm = 72 cm

Total surface area of the solid = Curved surface area of the cylinder + Curved surface area of the hemispherical ends

= (2rh +2x 2r2)

= 2r(h+2r)

Rate of polishing = 7 paise per sq. cm.

Cost of polishing = Rs. = Rs. 855.36

Answered by  | 18th Feb, 2014, 11:26: AM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.