The terms and properties of lines, angles, and circles may be applied in the layout, design, development, and construction of closed flat shapes. A new term, plane, must be understood in order to accurately visualize a closed, flat shape. A plane refers to a flat surface on which lies a straight line connecting any two points. A plane figure is one which can be drawn on a plane surface. There are many types of plane figures encountered in practical problems. After this chapter, students should be able to calculate the perimeter and area of selected plane figures. In all, students will learn about:

1) Triangles

2) Area and Perimeter of Triangles

3) Circles

4) Summary