Answer:
1. 42 cm²
2. 128 cm²
6. 66 cm²
Explanation:
In each case, I am using the front and back faces as bases with length and width. The bottom right dimension is the height.
1.
SA = 2(L + W)H + 2LW
SA = 2(3 cm + 2 cm)(3 cm) + 2(3 cm)(2 cm)
SA = 42 cm²
2.
SA = 2(L + W)H + 2LW
SA = 2(6 cm + 4 cm)(4 cm) + 2(6 cm)(4 cm)
SA = 128 cm²
6.
SA = 2(L + W)H + 2LW
SA = 2(3 cm + 3 cm)(4 cm) + 2(3 cm)(3 cm)
SA = 66 cm²