Plane Geometry is a branch of mathematics that deals with shapes and figures on a flat surface, known as a plane. It focuses on basic elements such as points, lines, angles, and various two-dimensional shapes like triangles, rectangles, and circles. In Plane Geometry, the relationships between these shapes are studied, including properties like area, perimeter, and congruence. This field is foundational for understanding more complex geometric concepts and is widely used in fields such as architecture, engineering, and art.