Answer: 18.08
===========================================
Work Shown:
The cylinder has volume of...
V = pi*r^2*h
V = 3.14*4^2*8
V = 401.92
----------------
The rectangular prism has a volume of...
V = L*W*H
V = 10*7*6
V = 420
----------------
Subtract the two results:
420-401.92 = 18.08
The cylinder has roughly 18.08 more cubic units of volume compared to the rectangular prism.