Given two triangles with three corresponding angles that are congruent, why can't the two triangles be proved congruent? a) given three congruent angles, only the longest side can be congruent. b) given three congruent angles, only the shortest side can be congruent. c) the triangles could have the same shape but not necessarily the same size. d) the triangles could have the same size but not necessarily the same shape.