Lets get started :)
The Volume formula of a Cylinder is 
V = 

r²h 
(r = radius, h = height)
The radius given is 8 and the height is 4, We can plug in the known values
V = 

(8)²(4)
 = 

256
 = 
256
 units³
 units³ (You can leave the answer in this form)
 ≈ 
804.2 units³ (approximately)
Units
³ because it is a volume (3D shape)