Answer:
The vertex of an angle is formed, if and only if the sides of the angles intersect or meet.
Explanation:
The definition of the vertex of an angle is - The vertex of the angle is the point, where the sides of the angle intersect.
A bi conditional statement is in the form of - p if and only if q.
Hence, the definition of the vertex of an angle as a bi conditional statement can be written as :
The vertex of an angle is formed, if and only if the sides of the angles intersect or meet.