This is a free lesson from our course in Algebra I
In this part of lesson you'll learn how to find the equation of a line perpendicular
to a given line. In such cases, we need to remember that in case of perpendicular
lines, the product of their slopes is 1. This gives us a way to find the slope of the
required equation 
if the slope of given line is m_{1}, the slope of perpendicular line will
be 1/ m_{1}.
The steps we need to take are as follows:
• calculate slope of the new line as described above.
• extract other information provided, e.g. the yintercept, a given point on that line etc.
• find the equation of the new line by using the slope and the other information provided
to us. (More text below video...)
(Continued from above)
Two lines or planes (or a line and a plane), are considered perpendicular (or orthogonal) to each other
if they form congruent adjacent angles (an Lshape). The term may be used as a noun or adjective.
In a coordinate plane, perpendicular lines have opposite reciprocal slopes.
E.g.: Write an equation of the line perpendicular to 4y  x = 20 and containing the point (2, 3).
Solution: Rewrite the equation in slopeintercept form.
y = .25x + 5
We know the slope of the perpendicular line is 4 because .25 * 4 = 1.
(Notice that the slope of the perpendicular line is the re ciprocal of the other line's slope.).
Now plug the given point and the slope into a slopeintercept equation to find the y intercept.
3 = (4)2 + b
Solve for b.
b = 5
Now, you have the information you need to write an equation for a line perpendicular to 4y  x = 20.
The answer is the following equation: y = 4x + 5.
Winpossible's online math courses and tutorials have gained rapidly popularity since
their launch in 2008. Over 100,000 students have benefited from Winpossible's courses...
these courses in conjunction with free unlimited homework help serve as a very effective
mathtutor for our students.

All of the Winpossible math tutorials have been designed by topnotch instructors
and offer a comprehensive and rigorous math review of that topic.

We guarantee that any student who studies with Winpossible, will get a firm grasp
of the associated problemsolving techniques. Each course has our instructors providing
stepbystep solutions to a wide variety of problems, completely demystifying the
problemsolving process!

Winpossible courses have been used by students for help with homework and by homeschoolers.

Several teachers use Winpossible courses at schools as a supplement for inclass
instruction. They also use our course structure to develop course worksheets.