Answer:
Undefined ( ∞ )
Step-by-step explanation:
The given line is y=1
It is horizontal line on coordinate plane.
Because y=k means y become constant and x varies.
If we draw <em>perpendicular</em> to horizontal line then it would be vertical line.
The equation of vertical line, x=h
The slope of horizontal line is 0
The slope of vertical line is undefined.
Because vertical line makes angle with x-axis 90°
Slope = tan 90°
∵ tan 90° is undefined.
Hence, The slope of perpendicular line of y=1 is undefined.