15. the volume of a right circular cylinder is represented by v = pi r^2 where r is
the radius of the base (in feet). what is the radius of a right circular cylinder
when the volume is 144pi cubic feet and the height is 9 feet ?
16. the cost c in dollars) of producing x widgets in represented by c = 4.5x^2. how
many widgets are produced if the cost is $544.50?
17. two squares are drawn. the larger square has area of 400 square inches. the
area of the two squares have a ratio of 1: 4. what is the side length of the
smaller square?