# KEVA® Polygons

=OBJECTIVE: Students will construct 10 different regular polygons and will demonstrate that the size of interior angles of regular polygons increases as the number of sides increases.

MATERIALS:

• 100 planks per student or small group

PROCEDURE:
1.
Have students work individually or in small groups. Tell the students that the interior angles of a regular polygon are all equal. Have each student or group con- struct the following regular polygons out of KEVA planks, laying blocks flat
or on their sides.

Figures

Triangle (3) Square (4) Pentagon (5) Hexagon (6) Heptagon (7) Octagon (8) Nonagon (9) Decagon (10) Undecagon (11) Dodecagon (12)

1. Students can label each polygon by writing the name and number of sides on a card.

2. Ask the students to notice what happens to the polygon as the number of sides increases. (Students will easily see that the overall size of the polygon increases. This is true in this activity because the KEVA planks are all the same size. This is a good observation but not the one we are after for this lesson.) Students should be able to see that as the number of sides increases, the size of each interior angle also increases. Younger students may express this by noticing that the figures are becoming more and more round.