Geometry- Triangle ABC has been dilated to form triangle A'B'C'. If sides AB and A'B' are proportional, what is the least amount of additional information needed to determine if the two triangles are similar? Angles B and B' are congruent, and angles C and C' are congruent. Segments AC and A'C' are congruent, and segments BC and B'C' are congruent. Angle C=C', angle B=B', and segments BC and B'C' are congruent. Segment BC=B'C', segment AC=A'C', and angles B and B' are congruent.