Question 184
In an acute triangle $ABC$ we consider its orthocenter, $H$. Let $A'$, $B'$ and $C'$ be the symmetrical $H$ with respect to the sides $BC$, $CA$ and $AB$, respectively. Prove that if triangles $ABC$ and $A'B'C'$ have an equal angle, then it also has an equal side. Is the reciprocal true?