Here the lengths are AB=10, BC=8 and AC=6 (to start with).[br]D and E lie between A and B so that AE=AC and BD=BC.[br]You can move the points A, B, D and E.[br]Note what happens to C as you move D towards B ...[br]What about when D reaches E ... and moves to beyond E (towards B)?[br]Move D back again between A and E, noticing all the while ...[br]Next, leave D fixed and move E ...[br]Finally move A (or B) so that AB is no longer horizontal ...[br]Write down everything your notice ...