please prove the mid point theorem

Hi!

Mid point theorem states that " the line segment joining the mid-points of any two sides of a triangle is parallel to the third side and equal to half of it".

⇒ ED | | BC      (Opposite sides of parallelogram are parallel)

⇒ EF | | BC 

EF = DF  (Proved)

⇒ EF + DF = ED = BC    (Opposite sides of the parallelogram are equal)

⇒ EF + EF = BC

⇒ 2 EF = BC 

Cheers!