What is the union of two coplanar half-planes an their common edge?

The union of two coplanar half-planes along their common edge forms a region that includes both half-planes and their shared boundary line. This region is essentially the entire plane on one side of the edge, encompassing all points in both half-planes. If the half-planes are defined by two lines intersecting at their common edge, the union will include all points on both sides of the edge, effectively covering a larger area.