Home

Construct a Line Perpendicular to Another Line Through a Point

|
Updated:  
2016-12-08 3:03:09
|
Geometry Essentials For Dummies
Explore Book
Buy On Amazon
Say you're taking a geometry test, and one question gives you a line along with a point that is not on that line. You're told to construct a line perpendicular to the given line that also passes through the point.

geometry-perpendicular

Can it be done? Well, yes—but you'll need a compass to make it happen.

The following figure will help guide you through a construction.

geometry-perpendicular-construct Constructing a perpendicular line through a point not on a line.

Now, follow these steps:

  1. Open your compass to a radius r (r must be greater than the distance from J to line AZ), and construct arc (J, r) intersecting line AZ at K and L.
  2. Leaving your compass open to radius r (other radii would also work), construct arc (K, r) and arc (L, r)—on the side of line AZ that's opposite point J—intersecting each other at point M.
  3. Draw line JM, and that's a wrap.

About This Article

This article is from the book: 

About the book author:

Mark Ryan has more than three decades’ experience as a calculus teacher and tutor. He has a gift for mathematics and a gift for explaining it in plain English. He tutors students in all junior high and high school math courses as well as math test prep, and he’s the founder of The Math Center on Chicago’s North Shore. Ryan is the author of Calculus For Dummies, Calculus Essentials For Dummies, Geometry For Dummies, and several other math books.