On the ray with the beginning of O, points A, B and C are marked so that point B

On the ray with the beginning of O, points A, B and C are marked so that point B lies between points O and A, and point A – between points O and C. Compare the segments OB and OA, OC and OA, OB and OC.

For clarity and convenience, we will depict these points graphically, fulfilling the condition that point B lies between points O and A, and point A – between points O and C.

О____В___А____С___

It is now obvious that:

1) ОВ <ОА,

2) OS> OA,

3) OB <OS.

On the other hand, one could reason like this: since all the compared segments have a beginning at the point O, then the segment whose end is located to the right of the ray will be large. Therefore, the largest segment is OS, then in descending order ОА and ОВ.