What is the slope of a line parallel to the y-axis?

2 Answers
Oct 6, 2014

Parallel lines have the same slope.

Vertical lines have an undefined slope.

The #y#-axis is a vertical.

A line that is parallel to the #y#-axis also has to be vertical.

The slope of a line parallel to the #y#-axis has a slope that is undefined.

Feb 21, 2017

Answer:

A line parallel to the y-axis - a.k.a. vertical line has no slope!

Explanation:

Slope is defined as #rise# divided by #run#

A line parallel to the #y# axis is a vertical line that has no #run# so it defies the definition.

A line parallel to the #x# axis has no #rise# but it follows the definition because a slope of #0# can be calculated.