To obtain the volume we must first know the volume of the full sphere.
Mathematically, volume of a sphere is given as 4/3(pi*r^3) where r is the radius of the sphere (60 feet in this case).
Thus, volume of a quarter sphere shaped tank will be 1/3(pi*r^3), quarter of a full sphere.
We simply substitute the value of r to obtain the volume. V = 226,195 ft^3. In other units, V = 6,405 m^3 (1 ft = 0.3048 m so 60 ft = 18.288 m)