This chord subtends an angle at the centre equal to 2arcsin(cos φ sin ) and the great circle distance between A and B is 2a arcsin(cos φ sin ).)
Anminnăk wen eqqal tangălt n as tasaja tahat ammăs togdăh id 2 arcsin (cos φ sin ) tolas tajililwăyt ta maqqorat jir A d B taqqal 2a arcsin cos φ sin )