This is a PP=Problem Picture, i.e. a ggb file for a screenshot.
The triangles are congruent, i.e. [math]\Delta ABC \cong \Delta \,\,\,\,\,\,\,\,\,\,\,\,\,\,\, [/math] Prove this.
The points A,B and C are all free.
Moving D moves the brown triangle, Moving E rotates the brown triangle, F is dependent.
Checking FLIPPED reflects the brown triangle (and inverts the order of vertices in congruence).
