The decorative block shown in fig. is made of two solids - a cube and a hemisphere. The base of the block is a cube with edge 5 cm, and the hemisphere fixed on the top has a diameter of 4.2 cm. Find the total surface area of the block.
(Use π = 3.14).
Let r cm be the radius and h cm be the height of a cone then.
Let r2 cm be the radius and h2 cm be the height of cylinder, then
r2 = 2 cm
and h2 = (2 + 2) cm = 4 cm
Now,
Volume of solid toy,
Volume of cone + Volume of hemisphere
Volume of cylinder,
Hence,
(i) Volume of toy = 25.12 cm
(ii) Difference of the volume of cylinder and the toy
= (50.24 – 25.12) cm3
= 25.12 cm3.