In the given figure, O is the midpoint of each of the line segments AB and CD. Prove that AC=BD and AC∥BD.
To prove: AC=BD and AC∥BD
In △AOC and △BOD, we have:
OA=OB (O is the midpoint)
∠AOC=∠BOD (Vertically opposite angles)
OC=OD (O is the midpoint)
∴△AOC≅△BOD (By SAS congruency criterion)
Also, ∠CAO=∠OBD (CPCT)
and, AC=BD (CPCT)
AC and BD is cut by a transversal AB, such that the alternate angles are equal i.e. ∠CAO=∠OBD
So, AC∥BD
and AC=BD (proved above)
Hence, proved.