Use the example below. Be careful about the Data(:,1)==37.1234 comparison though as it involves floating point. You may need to use abs(Data(:,1)-37.1234)<eps instead.
Data=[37.4321 8.9823 5
37.4321 8.9850 7
37.1234 7.6763 8
37.4321 8.9823 8
37.4321 8.9850 3
37.1234 7.6763 5];
Index=and(Data(:,1)==37.1234,Data(:,2)==7.6763);
MyData=Data(Index,3)
