The measure of the angle $\angle A$ of the acute triangle $ABC$ is $60^o$, and $HI = HB$, where $I$ and $H$ are the incenter and the orthocenter of the triangle $ABC$. Find the measure of the angle $\angle B$.
Problem
Source: 2011 Romania JBMO TST2 P4
Tags: geometry, incenter, orthocenter, equal segments, angles