The total surface area of a cube is 864 square cm. What will be its volume?

If the areas of circular ring having inner and outer radius 8 cm and 12 cm respectively is equal to the total surface area of cylinder of radius R₁ and height h, then h in terms of R₁ will be :

A rectangular grass plot 80 m × 60 m has two roads, each 10 m wide, running in the middle of it; one parallel to length and the other parallel to breadth. Find the cost of gravelling the roads at ₹ 2 per m². 

A cylindrical well of depth 21 m with internal radius of 13 m is dug up. The mud, so detained, is spread evenly to form a platform of dimension 52 × 13.2. What is the height of the platform?

The covered surface area of  a cone of radius 8 cm and height 6 cm is double the covered surface area of a cylinder of radius 4 cm. Find the height of the cylinder?

A circular park whose diameter is 210 m has a 5 m wide path running around it(on the outside). What is the area ( in m²) of the path?

The diameter of a circle is equal to the perimeter of a square whose area is 3136 sq cm. What is the circumference of the circle?

The base of a right prism is a tringle with sides 20 cm, 21 cm and 29 cm. If its volume is 7560 cm³, then its lateral surface area ( in cm²) is: