Solution:
Given:
OC is the point of intersection of AC and BD in the trapezium ABCD, with AB ∥ DC.
To prove:
OA/ OC = OB/ OD
Proof :
In ΔAOB and ΔCOD
∠AOB = ∠COD (Vertically Opposite Angles)
∠OAB = ∠OCD (Alternate angles)
ΔAOB ∼ ΔCOD
Therefore, OA/ OC = OB/ OD (Corresponding sides are proportional)