Answer:
h=8
Explanation:
there is a formula for a volume of a prism
Volume = length • width • height
for shortening purposes
V = L • W • H
we know the prism's length is 4, and it's width is 2 and we know it's volume is 64 but the height is missing
what we will do is say (since height is missing)

v = 64
l = 4
w = 2
so, now plug in those values for your variables

multiply 4 • 2

divide by 8

simplify

Check:
V = l•w•h
v= 4 • 2 • 8
v = 8• 8
v = 64
hope this helped happy learning