Question

25 circular plates each of radius 10.5cm  and thickness 1.6cm are placed one above the other to form a solid circular cylinder. Find the curved surface area and volume of cylinder so formed?

Answer 1

Given that 25 circular plates each with radius (r) = 10.5cm

Thickness = 1.6cm

Since plates are placed one above other so its height becomes =1.6 X 25 = 40cm

Volume of cylinder = πr²h

= π(10.5)² x 40

= 13860cm³

Curved surface area of a cylinder = 2πrh

= 2 x π x 10.5 x 40

=2 x 22/7 x 10.5 x 40

=2640cm²

∴Volume of cylinder= 13860cm³

Curved surface area of a cylinder = 2640cm²