资料来源 : pyDict

成三角形

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Triangularity \Tri*an`gu*lar"i*ty\, n.
   The quality or state of being triangular. --Bolingbroke.

资料来源 : WordNet®

triangularity
     n : the property of being shaped like a triangle