The comlete question with the diagram is in the picture attached.
Answer:
Point
is the vertex of the angle marked in the figure.
Explanation:
When two lines intersect each other they will form an <em>angle</em> and the intersection point will be the <em>vertex of the angle</em>.
In the figure attached, the line that joins the points A and B and the line that joins the points C and D intersect at the point E, forming the corresponding angle (shadowed in the figure).
Such intersection point, which marks the angle, is the vertex of the angle.