A cylindrical tank has a capacity of 3080m². What is the depth of the tank, if the diameter of its base is 14m?

A sector of circle of radius 7.2cm which subtends an angle of 300^oat the centre is used to form a cone. What is the radius of the base of the cone? 

A frustum of pyramid with square base has its upper and lower section as squares of sizes 2m and 5m respectively and the distance between them 6m. Find the height of the pyramid from which the frustum was obtained.