EAC = BAC / CPI
EAC = AC + ETC
EAC = AC + ((BAC – EV)/ CPI)
Or to re-phrase… The Estimate to Complete is the Actual Costs until this point added to the Estimated cost to finish the remainder of the Project
This is saying ETC = ((BAC-EV)/CPI) or If you subtract the current effort out of the plan you would have the remaining effort factor in the CPI and you can extrapolate what the remaining work will cost
You should know how to do the math magic, so you can extrapolate your projects completion