Assertion: rectangle's diagonal | /r/HasProperty | the edges of a tetrahedron
Facets:
Source sentences:
text: If they are straight lines (AB, BC, CD, DA) then they and the rectangle's diagonals (AC and BD) are the edges of a tetrahedron in which AC and BD do not intersect so a saddle rectangle (a skew rectangle whose diagonals intersect) does not exist.