GeoGebra Classroom

# Segments and Midpoint

## Constructing midpoint of line segment AB

In the following GeoGebra applet, follow the steps below: -Select the COMPASS tool (Window 5). Then click on line segment  CD (represents the opening length of the compass) and then on the point A. Then click on line segment  CD (represents the  opening length of the compass) and then on the point B.   -Select the INTERSECT (Window 3) and mark the intersections E and F of the two circles.   - Select the SEGMENT tool (Window 4) and draw a line segment with endpoints E and F. - Select the INTERSECT tool (Window 3) and mark the intersection of line segments AB and EF. Change the name of the point to M. - Select the SHOW/HIDE OBJECT tool (Window 6) and hide the circles and the line segment EF, leaving only the line segment AB and the point M. NOTE: you can hide the objects by clicking on it with the right button and choosing the option "Show object". - Select the tool DISTANCE OR LENGTH (Window 7) and click on A and then on M. Then click on B and then on M. What do you see? What is a “Midpoint”? Points A and B are said to be symmetric in relation to point M, which is considered the center of symmetry. - Select the tool MOVE (Window 1) move point A or B. Observe.