# Isosceles Tutorial: Bisecting a Line Traditionally

Many geometry techniques require you to bisect a line. In this tutorial you will learn how to find the midpoint and perpendicular bisector of a line. First, ensure that Shows Intersections is turned on in the Canvas pane of the Settings.

1. Create a point to start the line.

2. With the Line Tool selected, drag from the point to create the line to bisect. (Obviously, you will not need to do this if you already have a line to bisect!)

3. Select the Arc tool. The compass should appear in the middle of the screen.

4. Move the compass to point A by dragging the center handle. Drag the compass arm to rotate it to the position shown.

5. First tap the pencil icon to switch to the light pencil (for intermediate measurements). Drag the outer handle of the compass up the circle to draw an arc. Then rotate the compass arm down, and draw another arc.

6. Move the compass to point B and repeat.

7. Choosing the Line tool will hide the compass (any tool will do, but we need the Line tool), showing your arcs:

8. Draw a line between the intersections of the pairs of arcs. This is the perpendicular bisector, and its intersection with the original line is the midpoint of line AB.

9. To make the bisector longer, tap and hold on it, tap again to show the menu, then tap Info in the menu. Turn on Extends. Now pick any two points on the line, connect them, and delete the original line.