Area of Triangles

Below shows △ABC.

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


Instructions:

1. Adjust the size of △ABC.
2. Check the boxes.
3. Observe the area of △ABC obtained by both methods.
4. Compare both formulae.
5. Repeat steps 1 ~ 4 for other sizes of △ABC.

Download the GeoGebra file: http://www.geogebratube.org/material/download/format/file/id/44999

Download the Worksheet: http://db.tt/O5TJ2ZPM