A spherical gas tank has a 10 foot diameter when filled with propane it provides 358,000,000 BTUs how many BTUs does 1 cubic foot of propane yield? Round to the nearest thousand

Volume of the spherical tank will be given by:
V=4/3πr³
thus the volume of the tank will be:
V=4/3×π×(10/2)³=523.59877756~523.6 ft³
Given that 523.6 ft³ can hold 358,000,000 BTUs of propane, the amount that 1 ft³ will be given by:
[total amount]/[total volume]
=358,000,000/523.6
=683,728.0367 BTUs/ft³
=684,000 BTUs/ft³ (in thousand)