The length of the boundary of a closed figure is called the perimeter of the plane figure. The units of the perimeter are same as that of length, i.e., m, cm, mm, etc. Area: A part of the plane enclosed by a simple closed figure is called a plane region, and the measurement of the plane region enclosed is called its area. A plane figure is made of line segments or arcs of curves in a plane. It is a closed figure if the figure begins and ends at the same point. We are familiar with plane figures like squares, rectangles, triangles and circles. Students will learn how to find the area and perimeter of a plane geometrical figures with the help of various solved problems.