• chapter 12

    Angles, Lines, and Two-Dimensional Figures

    lines and angles

    In earlier grades, students have learned to distinguish between lines and curves and have explored basic shapes such as circles, triangles, and squares.  They learned that combining or decomposing plane shapes produced other shapes and have had the opportunity to draw shapes on dot paper and grid paper.

    Their previous exposure to angles and shapes helps to lay the foundation for students to recognize angles, perpindicular lines and parallel lines, and to explore polygons.  They will now be ready to draw angles, lines, and figures.

    In this chapter, students will apply what they know about lines and angles to help them identify the sides and angles of closed figures.  They will learn that an angle is formed when two lines meet at a point.  An emphasis will be placed on the idea that an angle is not determined by the lengths of the lines that make up the angle.  

    It is important for students to know the difference between lines and line segments as both terms are used when dealing with perpendicular and parallel lines.  They will learn to classify polygons and are taught the names given to special polygons and quadrilaterals.

     This chapter will serve as a basic understanding for angles and polygons.  Students will use this understanding for measuring angles in Grade 4 and more complex geometric shapes in later grades.