Best Approximations of Convex Compact Sets by Balls in the Hausdorff Metric

We deduce an upper bound for the Hausdorff distance between a nonempty bounded set and the set of all closed balls in a strictly convex straight geodesic space $X$ of nonnegative curvature. We prove that the set $\chi[M]$ of centers of closed balls approximating a convex compact set in the Hausdorff metric in the best possible way is nonempty $X[M]$ and is contained in $M$. Some other properties of $\chi[M]$ also are investigated.