Answer:
18
Step-by-step explanation:
The formula of a volume of a rectangular prism:
[tex]V=lwh[/tex]
l - length
w - width
h - height
We have l = 3, w = 3 and V = 54. Substitute:
[tex]54=(3)(3)(h)[/tex]
[tex]54=9h[/tex] divide both sides by 9
[tex]6=h\to h=6[/tex]
The perimeter of the shaded face:
[tex]P=2h+2w[/tex]
Substitute:
[tex]P=2(6)+2(3)=12+6=18[/tex]
