The cross section of a drainage is parabolic in shape. When the width of the water surface is 10 metres, the maximum depth of the water is 1.5 metres. Determine the width of the water, w, when the maximum depth is 3 metres.

A cylindrical container has a volume of 84 cubic inches and a radius of 3 inches. Find the height of the container.

The area of the face of a Ferris wheel varies directly with the square of its radius. If the area of one face of a Ferris wheel with diameter 150 feet is 70,650 square feet, what is the area of one face of a Ferris wheel with diameter of 16 feet?