A hollow iron pipe is 21 cm long and its exterior diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weights , then the weight of the pipe (π) is. 

The length of the diagonal of a square is 'a' cm. Which of the following represents the area of the square (in sq. cm)? 

The height of a square base right prism is 15 cm. If the total surface area of the prism is 608 cm² , then what will be the volume of prism?

Find the area of a white sheet required to prepare a cone with a height of 21cm and the radius of 20cm.

The length of a hollow thick cylindrical metallic pipe is 6 cm and its total surface area including the surface at the ends is 98π sq. cm. If the outer diameter is 8 cm, then the inner diameter in cm is 

From a circle of radius a, a sector, which subtend an angle π/5 at the centre has been cut off. The perimeter of the remaining part of the circle is

A solid metallic cylinder of base radius 5 cm and height 7 cm is melted to form cones, each of height 1 cm and base radius 1 mm. Find the number of cones?

The ratio of the areas of two isosceles triangles having the same vertical angle is 1 : 9.The ratio of their heights is -