例句與造句

1. In geometry, "'Poncelet's porism "'( sometimes referred to as "'Poncelet's closure theorem "') states that whenever a polygon is inscribed in one conic section and circumscribes another one, the polygon must be part of an infinite family of polygons that are all inscribed in and circumscribe the same two conics.
2. In fact the converse also holds : given two circles ( one within the other ) with radii " R " and " r " and distance " x " between their centers satisfying the condition in Fuss'theorem, there exists a convex quadrilateral inscribed in one of them and tangent to the other ( and then by Poncelet's closure theorem, there exist infinitely many of them ).
3. It's difficult to find closure theorem in a sentence. 用closure theorem造句挺難的