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 

A regular hexagon has a side of 4 cm. Find its area. (in sq. cm)

The length, breadth and height of a room is 21 metres, 12 metres and 16 metres. What will be the length of the largest rod that can be placed in that room?

A semicircle is folded to make a cone. Find the height (in cm) of the cone if diameter of the semicircle is 28 cm?

The ratio of the areas of two isosceles triangles having the same vertical angle is 1 : 9.The ratio of their heights 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 length of a rectangle is 6 cm more than its width and its perimeter is 100 cm. If the area of this rectangle is closest to the area of a circle, then what is the circumference of that circle?

A shuttlecock used of playing badminton has the shape of a frustum of a cone mounted on a semi sphere. The external diameters of the frustum are 5 cm and 2 cm, the height of the entire shuttlecock is 7 cm. The external surface is of the shuttlecock is: