Question:
30 circular plates, each of radius 14 cm and thickness 3 cm are placed one above the another to form a cylindrical solid.
Find
- the total surface area.
- volume of the cylinder so formed.
Solution:
Given, radius of a circular plate, r = 14 cm
Thickness of a circular plate = 3 cm
Thickness of 30 circular plates = 30 x 3 = 90 cm
Since, 30 circular plates are placed one above the another to form a cylindrical solid. Then, Height of the cylindrical solid, h = Thickness of 30
circular plates = 90 cm
- Total surface area of the cylindrical solid so formed
= 2πr(h+ r)=2 x (22/7) x 14(90+ 14)
= 44 x 2 x 104 = 9152 cm2
Hence, the total surface area of the cylindrical solid is 9152 cm2, - Volume of the cylinder so formed = πr2h
= (22/7) (14)2 x 90 =(22/7) x 14 x 14 x 90
= 22 x 28 x 90 = 55440 cm3
Hence, the volume of the cylinder so formed is 55440 cm3.