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

A farmer connects a pipe of internal diameter 20 cm from a canal into a cylindrical tank in her field which is 10 m in diameter and 2 m deep. If water flows through the pipe at the rate of 3 km// h, in how much time will the tank be filled ?

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 .

The curved surface area of a cylinder is 110 cm^(2) and its diameter is 7 cm. Find the height of the cylinder.

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.

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 si 7 cm Then find the total volume of 50 such rods.

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.

The length, breadth and height of a cuboid are 20 cm, 15 cm and 10 cm respectively. Find the area of its lateral surfaces.

In a hot water heating system, there is a cylindrical pipe of length 28 m and diameter 5 cm. Find the total radiating surface in the system.