30 circular plantes, each of radius 14 cm and thickness 3 cm are placed one above the another to from a cylindrical solid . Find
(i) the total surfce area.
(ii) volume of the cylinder so formed.

Explanation

Clearly, the cylinder formed has base radius, r = 14 cm and height, `h = (3 xx 30) cm = 90 cm`
(i) Total surface area of the cylinder formed
`= (2pi rh + pi r^(2)) = 2pi r (h + r) cm^(2)`
`= {2 xx (22)/(7) xx 14 xx (90 + 14) } cm^(2)`
`= (88 xx 104) cm^(2) = 9152 cm^(2)`
(ii) Volume of the cylinder formed
` = pi r^(2) h = ((22)/(7) xx 14 xx 14 xx 90) cm^(3)`
`= 55440 cm^(3)`