From your description of them being at the " top " and " bottom " of the " X ", it seems as if they might be vertical angles ( or " opposite angles " as we would say in UK ).
42.
In geometry, capital A, B, C etc . are used to denote rays, etc . A capital A is also typically used as one of the letters to represent an angle in a triangle, the lowercase a representing the side opposite angle A.
43.
The Nix film is considered by historians and other experts to be the second most important piece of footage because it was filmed from the opposite angle of the Abraham Zapruder film and shows what was going on behind Zapruder in the grassy knoll.
44.
The quadrilateral APBC is cyclic iff a pair of opposite angles ( such as the angle at P and the angle at C ) are supplementary i . e . iff \ alpha + \ beta + C = k \ pi, ( k = 1, 2, \ cdots ).
45.
The Encyclopedia Britannica's Literature Year In Review 1995 said of his novel Stand In Hell'. . . focused on the Holocaust from an opposite angle . . . the story of a teacher with his own sins to contend with who searches for the truth about his grandfather s complicity in Nazi war crimes .'
