9*15=135
15*4.8=72
9*4.8=43.2
135+72+43.2= 250.2ft (Surface Area)
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9*15*4.8=648ft (Volume)
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Hope this helps
I don't why you put -+ but I will go ahead and assume that it is -2.
4-+6
I think it is saying 4 - positive 6 but I'm guessing.
Add up all the rainfall amounts and divide by 11