Create a Perpendicular Line Through a Point NOT on the Line
To construct a line perpendicular to a given line through a point that is NOT on the given line, we first create a line segment whose perpendicular bisector will go through the given point.
1) Use the Compass tool to create a circle with center P that is large enough to intersect the given line in two places.
2) Mark the points where the circle and original line intersect.
3) Proceed as in the previous example. Be sure to check your angle using the Angle Measure tool
.