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Ben Barber
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Yes, every inner face must be a triangle, as chords drawn outside a cycle prevent a drawing from being outerplanar. Drawings of chordal graphs are then just triangulations of polygons; conversely, every triangulated polygon is outerplanar (certainly) and chordal (by induction, as cycles are sub-[triangulated polygons]).

Ben Barber
  • 4.6k
  • 2
  • 25
  • 38