to find the surface area, you need to find the area of all 6 sides using the dimensions given. each visible side has an opposite side that has the same dimensions.
1) 6*2=12
2) 6*2=12
3) 9*2=18
4) 9*2=18
5) 9*6=54
6) 9*6=54
then, you have to add all 6 sides together.
12+12+18+18+54+54
24+36+108
60+108
168 cm squared is the surface area