Assertion: ellipse's point | /r/AtLocation | circle
Facets:
Source sentences:
text: ,} The four points are on a circle if and only if the angles at P 3 {\displaystyle P_{3}} P 4 {\displaystyle P_{4}}
text: The four points are on a circle, if and only if the angles at P 3 {\displaystyle P_{3}} P 4 {\displaystyle P_{4}} ( x 4 − x 1 ) ( x 4 − x 2 )