Answer to Question #16769 in Differential Geometry for maria
line segment ab =6 line segment cd=5 what is line segment ad ?
Let's assign operator |AB| as a length of a segment AB. Then
|ad| = |ab| + |bc| + |cd| = 6 + |bc| + 5 = 11 + |bc|,
where |bc| is the unknown lenghth of a segment bc.