Answer:
936pi (approx. 2940)
Step-by-step explanation:
Volume of a sphere = (4/3)×pi×r³
V1 with r = 3 ft
V1 = (4/3)×pi×3³ = 36pi
V2 with r = 9ft
V2 = (4/3)×pi×9³ = 972pi
Increase = 972pi - 36pi = 936pi ft³
Which is approximately 2940 ft³ correct to 3 significant figures
