Apart of a line that starts at one endpoint and extends forever in one direction is a

It is called a ray.
segments have two end points. and a ray has one end point ad extends forever in one direction, and a line extends forever in both directions.

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)