In figure A, B, C, and D, E, F are two sets of collinear points, Prove that AD ∥ CF. [2 MARKS]
Concept: 1 Mark
Application: 1 Mark
In order to prove that AD ∥ CF, it is sufficient to prove that
Since ABED is a cyclic quadrilateral.
∴ ∠1+∠2=180∘ ....(i)
Now, BCFE is a cyclic quadrilateral and in a cyclic quadrilateral an exterior angle is equal to the opposite interior angle.
∴ ∠2=∠3 ....(ii)
From equations (i) and (ii), we get