Acylindrical chemical storage tank mush have a height 4 meters greater than the radius of the top of the tank. determine the radius of the top and the height of the tank if the tank must have a volume of 15.71 cubic meters

Radius of cylindrical tank top = r (meters) Height of cylindrical tank = r + 4 (meters) Volume of cylindrical tank =15.71 cubic meters Volume of cylinder = pi X r^2 X h So, 15.71 = (22/7) X r^2 X (r+4) So, r^3 + 4r^2 = (15.71 X 7 / 22) So, solving for r in: r^3 + 4r^2 - 4.99863636364 = 0 r = -3.61817 or -1.38171 or 0.999876 However, since r can only be positive, the correct answer is 0.999876 m Therefore, radius at the tank top = 0.999876 m and tank height is 4 + 0.999876 m = 4.999876 m