Answer:
C. 468mm²
Step-by-step explanation:
The formula for the surface area of rectangular prism is:
[tex]A=2(wl+hl+hw)[/tex]
Let's break down our variables.
L = 12mm
W = 6mm
H = 7mm + 2mm = 9mm
Now we substitute our values in the formula:
[tex]A=2((6)(12)+(9)(12)+(9)(6))[/tex]
[tex]A=2(72+108+54)[/tex]
[tex]A=2(234)[/tex]
[tex]A=468mm^{2}[/tex]
