Given : FA is a ray.
Find out the pair of angles share the common side FA.
To proof
As shown in the diagram
∠ BAF and ∠DAF are th.e pair of angles shares FA as a common side
REASON
Adjacent Angles are those angles that share a common side, a common vertex, and no common interior points.
as ∠ BAF and ∠DAF shares common vertex A and common side FA.
Therefore
∠ BAF and ∠DAF are th.e pair of angles shares FA as a common side