1.	The diagonal of a cube is 6√3 cm. Find its volume and surface area.
	Sol. Let the edge of the cube be a. ∴ √3a = 6 √3 ⇒ a = 6. So, Volume = a³ = (6 * 6 * 6) cm³ = 216 cn³ Surface area = 6a² = (6 * 6 * 6) cm² = 216 cm²
2.	Find the volume and surface area of a cuboid 16m long, 14m broad and 7m high.
	Sol. Volume = (16 * 14 * 7) m³ = 1568 m³ Surface area = [2 (16 * 14 + 14 * 7 + 16 * 7)] cm² = (2 * 434) cm² = 868 cm².
3.	If the capacity of a cylindrical tank is 1848 m³ and the diameter of its base is 14m, then find the depth of the tank.
	Sol.Let the depth of the tank be h metres. then, ∏ * (7)² * h = 1848 ⇔ h = [1848 * 7/22 * 1/7*7] = 12 m.
4.	How many iron rods, each of length 7m and diameter 2cm can be made out of 0.88 cubic metre of iron?
	Sol. Volume of 1 rod = [22/7 * 1/100 * 1/100 * 7] cu. m = 11/5000 cu.m. Volume of iron = 0.88 cu. m. Number of rods = [0.88 * 5000/11] = 400.
5.	A cube of edge 15 cm is imersed completely in a rectangular vessel containing water. If the dimensions of the base of vessel are 20 cm * 15 cm, find the rise in waer level.
	Sol. Increase in volume = Volume of the cube = (15 * 15 * 15) cm³. ∴ Rise in water level = [Volume/Area] = [15 * 15 * 15/20 * 15] cm = 11.25 cm.
6.	How many spherical bullets can be made out of a lead cylinder 28 cmhigh and with base radius 6 cm, each bullet being 1.5 cm ub duaneter?
	Sol. Volume of cylinder = (∏ * 6 * 6 * 28) cm³ = (36 * 28) ∏ cm³. Bolume of each bullet = [4/3 ∏ * 3/4 * 3/4 * 3/4] cm³ = 9∏/16 cm³. Number of bullets = Volume of cylinder / Volume of each bullet = [(36 * 28)∏ * 16/9∏] = 1792.