You can extend entities so that they end at a boundary defined by other entities. You can also extend entities to the point at which they would intersect an implied boundary edge. When extending entities, you first select the boundary edges, and then specify the entities to extend, selecting them either one at a time or using the fence selection method.
You can extend arcs, lines, two-dimensional polylines, and rays. Arcs, circles,
ellipses, lines, splines, polylines, rays, infinite lines, and layout viewports
on a Layout tab can act as boundary edges.
How do I...
Extend an entity
Extend an entity to an implied boundary
Extend several entities using the fence selection method