Question

20.
The front compound wall of a house is decorated by wooden spheres of diameter 21 cm, placed (4)
on small cylindrical supports as shown in the following figure. Eight such spheres are used for
this purpose and are to be painted silver. Each support is a cylinder of radius 1.5 cm and height
7 cm and is to be painted black
3
(a) Find the volume of each of the cylindrical support.
(i) 15.75 7 cm
(ii) 63 1 cm
(iii) 10.5 1 cm
(iv) 126 1 cm
(b) If silver paint costs 25 paise per cm² , find the cost of painting 8 wooden spheres.
(0) 441 1
(ii) 110.257
(iii) 588211
(iv) 17641
(c) Which of the following is the formula to find curved surface area of a cylinder of radius r сm and
height h cm?
(i) 4rrh cm?
(ii) 2nr’h cm?
(iii) 2nrh+ 2nr cm?
(iv) 2nrh cm?​

Answer 1

Answer:

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