Using 9.1, if you create 4 new fields and separate the Calculator equation, the correct results can be achieved.In the 1st field, calculate: ([X_beforeOffset]- [X_afterOffset])*([X_beforeOffset]- [X_afterOffset])In the 2nd field, calculate: ([Y_beforeOffset] - [Y_afterOffset])*([Y_beforeOffset]- [Y_afterOffset])In the 3rd field, calculate: [1st field] + [2nd field]In the 4th field, calculate: sqr([3rd field])This produces the correct results.