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
