Answer:
30 square millimeters
Step-by-step explanation:
3 x 3 = 9
3 x 1 = 3
there are two sides with the area 9 therefore...
9 x 2 = 18
There are four sides with the area 3 therefore...
3 x 4 = 12
Therefore the suface area is
12 + 18 = 30
