STANDARD G.CO.D.12
GEO

Make, justify, and apply formal geometric constructions.
• Examples of constructions include but are not limited to:
   o Copy segments and angles.
   o Bisect segments and angles.
   o Construct perpendicular lines including through a point on or off a given line.
   o Construct a line parallel to a given line through a point not on the line.
   o Construct a triangle with given lengths.
   o Construct points of concurrency of a triangle (centroid, circumcenter, incenter, and orthocenter).
   o Construct the inscribed circle of a triangle.
   o Construct the circumscribed circle of a triangle.
   o Constructions of transformations. (see G.CO.A.5)
• This standard is a fluency recommendation for Geometry.  Fluency with the use of construction tools, physical and computational, helps students draft a model of a geometric phenomenon and can lead to conjectures and proofs.