Answer:
288π units^3≈904.32 units^3
Explanation:
The volume of a sphere is (4/3)πr^3. (r=radius)
You're given the radius: 6 units. Just plug r into the formula. (V=volume)
V=(4/3)πr^3
 =(4/3)π(6)^3
 =(4/3)*6*36π (3 and 6 are underlined b/c I canceled them out to leave 4*2)
 =4*2*36π
 =4*72π
 =288π units^3
 ≈288*3.14 (this is if you use 3.14 for π)
 =904.32 units^3 
Hope I could help you!