d,e,f are the mid points of the sides bc, ca,and ab respectively of triangle abc. then triangle def is congruent to triangle:

- triangle abc
- triangle aef
- triangle bfd,cde
- triangle afe,bfd,cde

Note that FE will be parallel to BC and also half of it. This can be understood by learning the mid-point theorem and its converse.

Hence, FE = BD = DC.

Similarly, ED = QF = FB and FD = AE = EC.

Hence by SSS we have the four triangles DEF, AFE, FBD and EDC congruent. Option 4 is correct.

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