  Defining a robust measure of quantum correlation for multipartite states is
an unresolved and challenging problem. Existing measures of quantum correlation
are either not scalable or do not satisfy all the accepted properties of a
measure of quantum correlation. We introduce a novel geometric measure of
quantum correlation that we refer to as quantum reactivity. This measure is
extendable to an arbitrary large number of qubits and satisfies the required
properties of monotonicity and invariance under unitary operations. Our
approach is based on generalization of Schumacher's singlet state triangle
inequality that used an information geometry--based entropic distance. We
define quantum reactivity as the familiar ratio of surface area to volume. To
accomplish this, we use a generalization of information distance to area,
volume and higher--dimensional volumes. We examine a spectrum of multipartite
states (Werner, W, GHZ etc.) and demonstrate that the quantum reactivity
measure is a monotonic function for quantum correlation which satisfies all the
properties of a measure for quantum correlation, and provides an ordering of
these quantum states as to their degree of correlation.
