The equation for the volume of a rectangular prism is: V=lwh
Where V = volume, l = length of base, w = width of base, and h = height of prism.
By looking at the rectangular prism, you can see that you're given the width, w=4cm, the length, l=2cm, and the height, h=6cm. (These values can be switched around if you want and you'll still get the same final answer!).
Plug these values into the equation for volume of a rectangular prism:
[tex]V=lwh\\
V=(2\:cm)(4\:cm)(6\:cm)\\
V=48\:cm^{3} [/tex]
----
Answer: Volume = 48 [tex]cm^{3}[/tex]