Conic by half-turn
Prove that if A', B', C' are the images of any three points A, B, C after a half-turn about O, then the six points A', B', C', A, B, and C lie on a conic.
Drag points A, B, C or O to change the conic.
View completed construction at Halfturn conic 2
Created by Michael de Villiers, 14 Nov 2007 with Cinderella