The volume of a sphere is 4/3 * pi * radius^3. So the equation is 4/3 * pi * 7.5^3. First of all, 7.5^3 = <span>421.875. Then you 4/3 * pi * 421.875. 4/3 * 421.875 = 562.5. Then you do 562.5 x pi. <span>If you use pi as 3.14, then the answer is 1766.25. If you use pi as 3.14159, then the answer is </span></span><span>1767.144375. If you're crazy and use pi as 3.141592653589793238462643383279502884197 then the answer is roughly 1</span>767.145867644259. Hope I helped! :)