The Classroom Model or Manipulative
To assemble the model:
1st: Make the desired number of copies of the template and distribute these with scissors to each student.
2nd: Cut out, leaving line segments and arcs intact, the three shapes on the template -- two rectangles and one net of rectangles and quarter circles.
3rd: The quality of the model improves if one scores all dashed lines with a pencil or ball-point pen. Be particularly accurate in scoring the radii of the quarter circles since these provide rigidity to the model and obviate the need for tape, glue, or paper clips to hold the rectangular box together.
4th: Fold the paper back and forth on each of the dashed segments.
5th: Fold the printed side into the interior of the box, and pieces of the quarter circles to the exterior of the box. Fold the quarter circles to the short ends of the box. Paper clips or fingers may be used to hold the box together for examination.
6th: Place one of the rectangular sheets containing segment AB in the container so segment AB lies between points A and B. If the rectangular sheet is too large to fit cleanly in the rectangular container, trim off the short segment BD and/or the short segment opposite BD. The model is now ready for use.
Copies of the rectangular box might be made of paper or on acetate. If made of paper, students could construct the model then hold it in their hands for examination. If made of acetate, each rectangle in the net should be cut out separately and taped with transparent tape for permanent assembly and prior to use on an overhead projector.