Try this starting in A1.

6.6 13657 178.3 70.2 67.79
6.7 13886 179.9 70.36 67.68


6.67 13817.3 179.42 70.312 67.713

A5 contains your calculated value. B5 contains the following formula which
is copied to C5, D5 and E5.

=(1-(($A$2-$A5)/($A$2-$A$1)))*(B$2-B$1)+B$1

I did change the value in D2 because it is lower than D1. If your data is
really variable like that, you could modify the formula to accommodate it.

HTH


"hellmouthpirate" wrote:

I will try to explain this the best I can.

I have to do a calcualtion.
The answer to that calculation will then be used to look up data in a table.

For Example
A B C D
6.60 13657 178.3 70.20 67.79
6.70 13886 179.9 70.16 67.68

My calculated answer was 6.67.
How do I write a formula so that excel will return the corresponding values
for A B C & D for 6.67.

I have tried but the VLOOKUP function but it keeps returning the lower
values which is not what I want.


Yours hopefully
Simon