10 circular plates each of thickness 3 cm, each are placed one above the other and a hemisphere of radius 6 cm is placed on the top just to cover the cylindrical solid. What is the volume of the solid so for formed?

If 10 circular plates each of thickness 3 cm, each are placed one above the other, then it forms a cylinder with height (3 x 10 = 30 cm) and a hemisphere of radius 6 cm is placed on the top just to cover the cylinder that means its radius is 6 cm also
∴ Radius of hemisphere (R) = 6 cm
Radius of cylinder (r) = 6 cm
and height of cylinder (h) = 30 cm
∴ Volume of the solid = Volume of cylinder + Volume of hemisphere
= πr²h + (2/3)πR³
= π(6)² x 30 + (2/3)π(6)³
= π x 36 x 30 + (2/3)π x 216
= 1080π + 2π x 72 = 1080π + 144π
= 1224π cm³
Which is the required volume of solid.