Math Background

Polygons and Solid Figures: When Students Ask

  • Why should I bother learning this?
    This is an excellent opportunity to have your students look around the classroom, school, or community for examples of polygons and solid figures. Encourage them to imagine a workspace or a play area without certain polygons and solid figures. What would the world look like with only squares and cubes?
  • Is a square the same as a rectangle?
    Many students interchange the terms square and rectangle. List the properties of a square and rectangle side by side on the board so students can see the distinction between the two figures. Emphasize that a square is a special kind of rectangle.
    List of Rectangle and Square properties
  • Isn't a four-sided polygon called a rectangle?
    Tell students that a four-sided polygon is called a quadrilateral. A rectangle is a specific kind of quadrilateral. If students don't know the term quadrilateral, explain that the prefix quad- means “four.” To enhance students' understanding, show them many different quadrilaterals that are not rectangles.
  • How does understanding polygons help me learn about solid figures?
    Explain to students that the faces of some solid figures are polygons, so knowing polygons will help them identify solid figures. For example, all faces of a cube are squares and most of the faces of a pyramid are triangles.
  • Are the faces of rectangular prisms always rectangles?
    Your students can discover the answer to this question by constructing a rectangular prism from the net at the bottom of page 349 in the student book. Have volunteers draw nets to construct other rectangular prisms.
  • Will I ever need to find perimeter and area anywhere besides math class?
    Use this question to prompt a class discussion. Start with questions such as
    How could you find the amount of fencing needed to go around a playground? How could you find the amount of carpet needed to cover the floor of a room?

Houghton Mifflin Math Grade 3