Euclidean distance assumes the measurements are orthagonal. Mahalanobis or Statistical distance takes into account the correlations between the variables. My work uses Hotelling's T^2 statistic which is the squared statistical distance.
2.07735368677415 = Mahalinobis Distance = sqrt( v`S^-1 v)
4.31539833995416 = Hotelling's T^2 = v` S^-1 v
4.58257569495584 = Euclidean Distance = sqrt(v`v)
Inverse Covariance:
[ 5.284387181762E+01 -2.243048578668E+01 -9.722418962648E+00 ] [ -2.243048578668E+01 1.053532173500E+01 1.111849063008E+00 ] [ -9.722418962648E+00 1.111849063008E+00 1.325741924279E+01 ]