Midpoint Theorem

Below shows △ABC.

You can shift the points A, B and C to change the position and size of △ABC.


Instructions:

1. Adjust the position and size of △ABC.
2. Check the boxes.
3. Observe the ratio of the lengths of DE and AB.
4. Observe ∠CAB, ∠CBA, ∠CDE & ∠CED.
5. Repeat steps 1 ~ 4 for other positions and sizes of △ABC.

Download the GeoGebra file: http://www.geogebratube.org/material/download/format/file/id/45091

Download the Worksheet: http://db.tt/cptT3IAY