Given: In ΔDEF and ΔDGF, Side DF is common.
To prove congruent of the triangle, we must require the minimum three conditions; like two sides and one angle of one triangle should be equal to the other triangle. OR Three sides of one triangle should be equal to the other triangle. OR Two angles and one side of one triangle should be equal to the other triangle. etc.
As per given question, to prove congruent of given triangles by SAS property then we should have given two sides and one angle of one triangle should be equal to the other triangle as additional information.
Since, In ΔDEF and ΔDGF, Side DF is common. So, we should require only one side and one angle that should be equal to another triangle.
