Answer:
756pi unit^3.
Step-by-step explanation:
This is the sum of the volume of 3 spheres
V of a sphere = 4/3 pi r^3, so we have:
4/3 pi 2^3 + 4/3 pi 6^3 + 4/3 pi 7^3
= 4/3pi (2^3 + 6^3 + 7^3)
= 756pi.