# Isosceles Tutorial: Constructing Perpendicular Lines

In Isosceles, you can construct a line perpendicular to another line by turning on Snaps to Angles in the Snapping settings and drawing a line from a point on the original line that looks close to 90°. However, in some cases you may need to construct a perpendicular line using classical methods. First make sure you have Shows Intersections turned on in the Canvas pane of the settings.

1. We are given a line AB and a point C through which the perpendicular line must pass.

2. Choose the Arc tool, then drag the center handle of the compass to point C. Draw an arc (I used the light pencil) across line AB like this:

3. Move the compass center to one intersection of the arc and line AB and draw two arcs as shown. This method essentially resembles the method of constructing a perpendicular bisector.

4. Repeat the process with the other intersection.

5. Choose the Line tool and draw a line through point C and the two intersections we just created. This line is perpendicular to line AB.

Please leave a response if you have a question!