1. You have that the diameter of the spherical tank is diameter of 30 feet. Then, you must apply the formula for calculate the volume of a sphere:
 V=4πr³/3
 r=30 feet/2
 r=15 feet
 2. The volume of the tank is:
 V=4πr³/3
 V=4π(15 feet)³/3
 V=42,411.50 feet³/3
 V=14,137.16 feet³
 3.  The water weighs approximately 62 pounds per cubic foot , then:
 1 foot³-------62 pounds
 14,137.16---x
 x=876,504.35 pounds/foot³
 The answer is: 876,504 pounds/foot³
