A line segment
The endpoint.
A ray has a beginning but no endpoint.
No A line segment has a beginning and an end, but a line has no beginning or end. A ray has a beginning but no end.
The point at the beginning of a ray is called the "endpoint." A ray is a part of a line that starts at this endpoint and extends infinitely in one direction. The endpoint is crucial as it defines where the ray begins, distinguishing it from a line segment, which has two endpoints.
If you are only given one endpoint and a midpoint, you know what the middle of the line segment is. Since the midpoint is half of what the line segment's length is, all you have to do is find the distance between the endpoint given and the midpoint, then add that coordinate to your midpoint and get your other endpoint. For example: Endpoint A: (4,5) Midpoint: (6,8) Distance between: (2,3) Add (2,3) to (6,8) and get Endpoint B: (8,11).
Ray.
At the endpoint.
a ray
a ray
A ray.
-- Find the distance between the endpoint and the midpoint.-- Double that distance to get the length of the complete segment.-- When you're finished, sit quietly for a moment and ponder the meaning of "midpoint".
The direction of missing endpoint is the same as the direction from the known end point to the midpoint. The distance from the midpoint to the missing endpoint is the same as the distance from the known end point to the midpoint. In coordinate geometry it is simple. If the known end point is (p, q) and the mid point is (r, s) then the missing point is (2r - p, 2s - q).