Graph the line perpendicular to y=4 that passes through (-5, -2)

Answer 1

y = 4 is a horizontal line.

A line perpendicular to a horizontal line is a vertical line. Equations for vertical lines look like this:

x = some constant

If you know a point that the vertical line passes through, then you know that constant.

Give it a try!

Answer 2

All vertical lines are perpendicular to all horizontal lines. Horizontal lines have the form y=k, where k is a constant. One example is y=4.

Vertical lines have the form x=h, where h is a constant. Any point on that line will have the same constant as its value for x. That is, if (x,y) is part of a given vertical line, say x=h, then x=h is the x-coordinate of the pair. So,

x = -5

is the vertical line we seek.

Click on the link to see the graphs of

x = -5

and

y = 4.

https://www.desmos.com/calculator/hnemqxcv6b