Centroid (CRMQ) Mystery Cache

Welcome to the Capital Region Mathematics Quest. You are not looking for any secret information, but at some point, there may be available a cache for those who have completed all CRMQ caches.

This cache is an exercise in mathematics; geometry to be precise. Given below are the corners of Triangle ABC. This cache is found at the confluence of the three MEDIANS of the triangle. You are looking for a decon container.

Note: my measurements were taken using UTM although standard N/W should do the trick.