Illustration showing that the difference between angle 1 and angle 2 is angle ABC.
C. A. Hart & Daniel D. Feldman Plane And Solid Geometry (New York: American Book Company, 1911) 9
2400×729, 85.7 KiB
1024×311, 11.8 KiB
640×194, 6.9 KiB
320×97, 3.3 KiB