Question 1204093
What is the slope of a verticale and horizontal line?

The slope of the line is given by m = tan{{{theta}}} , where {{{theta}}} is the angle made by the given line with X axis.

A vertical line makes  angle {{{90^0}}}with the X axis. 

m=tan {{{90^0}}} is udefined  or infinity

A horizontal line is a line parallel to the  X  axis,  {{{ theta}}}=0

m=tan 0 = 0

 The slope of a vertical line is infinity; the slope of a horizontal line is zero.