Answer:
It is not clear but I think it is
Step-by-step explanation:
20,-18
-45
never mind i was wrong
5 is the mean
158
5*8=40
8*3=24
3*5=15
Each of these measurements gets added twice, becasue there are 6 faces on a rectangular prism.
40 + 40 + 24 + 24 + 15 + 15 = 158
2 ÷ 9 ≈ 0.222
√78 ≈ 8.832