Lines h and i, and points A,B,C,D,G, and K are coplanar in Plane J. An endpoint is a point at the end of a line segment. A line segment is a portion of a line with two endp...Lines h and i, and points A,B,C,D,G, and K are coplanar in Plane J. An endpoint is a point at the end of a line segment. A line segment is a portion of a line with two endpoints. A ray is a part of a line. Postulate #3: If a line and a plane share two points, then the entire line lies within the plane. What if you were given a picture of a figure or object, like a map with cities and roads marked on it? A city is usually labeled with a dot, or point, on a globe.