In the figure a regular nonagon and a regular triangle [i]ABO[/i] are given. [i]J[/i] and [i]K[/i] are midpoints of two neighbor sides of the nonagon. [i]L[/i] is the midpoint of the nonagon, [i]N[/i] is the midpoint of the arc [i]AI[/i] of the circumcircle of the nonagon. Finally, [i]M[/i] is the midpoint of the radius [i]LN[/i].[br]Prove that [i]JM[/i] is parallel to [i]OB[/i]. This is one formulation of [url=http://mathworld.wolfram.com/RegularNonagon.html]Karst's statement[/url].[br]GeoGebra can find an automatic proof by comparing [i]JM[/i] and [i]OB[/i] with the Relation tool. (As of August 2018 this statement cannot be completely proven with GeoGebra, just a numerical check can be performed.)