Measure to getting value from table using multiple variables

[luirib]

I need to write a DAX measure that will pull the rate from the below table (ER). My report will have a date and an entity, that will determine what rate is to be picked. For example, if I pick eas (see entities table below) and my month is Jan., the measure should show 60.333.

I think that the LOOKUPVALUE is intended for calculated columns only. Should I go CALCULATE(SUM(ER[Rate]), FILTER... [and here is where I get lost. I know that I need to include the country as a filter so it knows what conversion to use].

Thanks a lot.
This is the ER table

This is the Entities table

 

[Matt Allington]

Power Pivot is a model based tool. You build a model and then use it to extract the data. Join the entities[orcurr] to er[to]
you can then put date and code in a matrix with a simple measure like AVERAGE(er[rate])