GeoGebra Classroom

# Exploring Perpendicular Bisectors: Part 1

In the app below,
1. Use the SEGMENT tool to construct a segment with endpoints A and B.
2. Use the MIDPOINT tool to construct the midpoint of this segment. It should be named C.
3. Use the PERPENDICULAR LINE tool to construct a line perpendicular to segment that passes through the segment's midpoint C.

## This line you've just constructed is said to be the PERPENDICULAR BISECTOR of the segment AC. Keep going: More directions appear below.

4. Use the POINT ON OBJECT tool to plot a point D on the perpendicular bisector. 5. Now construct segments and . 6. Now select the MOVE tool. Then select (highlight) segment . Select the style bar icon (circle + triangle symbol in the upper right corner). Where it says "Aa", select Value. This will show its length. ' 7. Repeat step (6), yet this time for segment .

Now drag point D all along the perpendicular bisector of segment . What do you notice? Be specific!

Use the ANGLE TOOL to display . What is it? Why does it measure what it does?