If a parabolic reflector is 20 cm in diameter and 5 cm deep, find the focus.

A parabolic reflector is 40 cm in diameter and 10 cm deep. Find the position of the focus of the reflector.

A iron pillar consists of a cylindrical portion of 2.8 m height and 20 cm in diameter and a cone of 42 cm height sumounting it. Find the weight of the pillar if 1 cm^3 of iron weights 7.5 g.

By melting a solid iron sphere, 32 conical paper weights of equal volume is formed. If the height of Each paper weight is 4cm and the diameter of base is 1 cm, find the diameter of the sphere.

A women selfhelp group (DWACRA) is supplied a rectangular solid (cuboid shape) of wax block with dimensions 66 cm , 42 cm, 21 cm , to prepare cylindrical candles each 4.2 cm in diameter and 2.8 cm of height . Find the number of candles prepared using this so solid .

In the adjacent figure, the height of a solid cylinder is 10 cm and diameters is 7 cm . Two equal conical holes of radius 3 cm and height 4 cm are cut off as shown the figure. Find the volume of the remaining solid.

The shape of solid iron rod is cylinderical Its height is 11 cm and base diameter is 7 cm Then find the total volume of 50 such rods.

The height of a right circular cylinder is 12 cm and the diameter of the base is 7 cm. Find the area of its total surface.

How many silver coins, 1.75 cm in diameter and thickness 2 mm, need to be melted to form a cuboid of dimensions 5.5 cm xx 10 cm xx 3.5 cm ?

A hot water system (Geyser) consists of a cylindrical pipe of length 14 m and diameter 5 cm. Find the total radiating surface of hot water system.

A metal pipe is 77 cm .long .The inner diameter of a cross section is 4 cm. the outer diameter being 4.4 cm .Find its (i) inner curved surface area outer curved surface area Total surface area.