Using Basic proportionality theorem, prove that a line drawn through the mid-point of one side of a triangle parallel to another side bisects the third side. (Recall that you have proved it in Class IX).
Consider the given figure in which l is a line drawn through the mid-point P of line segment AB meeting AC at Q, such that PQ||BC.
Using basic proportionality theorem, we obtain
AQQC=APPB
⇒AQQC=11 (Since, P is the mid-point of AB, so AP=PB)
⇒AQ=QC
Hence, Q is the mid-point of AC.