answer:
Adjacent Vertices of a Quadrilateral: Two vertices which have a common side are called adjacent vertices. The pairs of adjacent vertices are (A, B); (B, C); (C, D) and (D, A).
explanation:
Discussions of 2-D shapes sometimes refer only to the boundary (the line segments that form the edges of the figure) or to the interior as well. When we talk about “dissecting” a parallelogram and rearranging the parts to form a rectangle in order to determine the area of the parallelogram, we are clearly referring to the edges and the interior. The usual definitions of polygons, however, refer only to the line segments that form the edges of the polygon. Most of the time, context will make clear what you mean, but you should remain aware that in some cases you may need to clarify.
https://elementarymath.edc.org/resources/shape-quadrilateral/
