In this configuration, there are specifically two rays represented by the triangle's horizontal line.
We have that a triangle having a horizontal line as its top would form an isosceles triangle.
When the horizontal line serves as the apex (or vertex) of the triangle, it divides the base into two equal halves.
Now, since there is an emerging ray from the vertex or top, an isosceles triangle with a horizontal line as its apex would be made up of two rays pointing in opposite directions along the line of symmetry.
Therefore, in this configuration, there are specifically two rays represented by the triangle's horizontal line apex.