Data: ABCD is a rhombus. Circle is drawn taking side CD diameter.
Let the diagonals AC and BD intersect at ‘O’.
To Prove: Circle passes through the point ‘O’ of intersection of its diagonals.
Proof: ∠DOC = 90° (Angle in the semicircle) and diagonals of rhombus bisect at right angles at ‘O’.
∴ ∠DOC = ∠COB = ∠BOA = ∠AOD = 90°
∴ Circle passes the point of intersection of its diagonal through ‘O’.