1. Make 10 regular pentagons with radii of 5 cm. (See our Making A Polygon lesson plan for instructions.)
If students are working individually, they may want to photocopy their pentagons so they won't have to construct all 10.
2. Find and mark the midpoint of each side on the pentagon. Connect the midpoints to make a smaller pentagon inside the larger one. Score (press hard on) these lines to help you fold them later. (Figure 1)
3. Cut out all the pentagons. Fold the tabs down along the lines connecting the midpoints. (Figure 2)
4. Attach two pentagons together by overlapping the tabs. Glue the tabs down. See "Attaching two pentagons" picture at left.
NOTE: It is easy to misunderstand this step. The tabs should not be glued to each other. The shaded tab is glued to the inside face of the right pentagon, and the unshaded tab is glued to the outside face of the left pentagon.
HINT: It helps to line up the fold lines when gluing the tabs.