We need to use the given diagram to find an angle congruent with ∠FJH. To do so, we need to remember that congruent angles have equal measures. Consider the given diagram.
Congruent angles are marked with an arc. If there is more than one set of congruent angles, each set is marked with the same number of arcs. Since ∠FCD and ∠ACB are both marked with two arcs, we have that ∠ACB is congruent with ∠FCD.