Other Figures

Age
6-9.

Materials

 * Reading labels: "trapezoid", "rhombus", "quatrefoil", "oval", "ellipse", "curvilinear triangle" or "Reuleaux triangle"
 * Frame of the circle inset (for presentation of ellipse)

Presentation

 * 1) Isolate the trapezoid and identify it (trapezoid: Greek: trapezion - a little table).
 * 2) In order to understand why this figure has its name we must go back in time to see what a table of the Greeks looked like.
 * 3) Nowadays our tables don't look trapezoidal.
 * 4) Some Spanish tables have two legs but still not trapezoidal.
 * 5) The Greek table was like a Spanish table because it had two legs, yet it was more stable because the legs were inclined.
 * 6) Isolate the rhombus and identify it.
 * 7) This is a rhombus (rhombus: Greek: rhombos - magic wheel, top)
 * 8) In ancient Greece, in the city of Athens, during a religious procession through the streets, a priest walked along with a cane (rod) raised over his head.
 * 9) At the end of the cane there was a cord attached, and at the end of the cord there was a rhombus-shaped figure attached.
 * 10) He rotated the cane in the air as he walked causing this figure to spin around like a top, making a characteristic sound.
 * 11) This was part of a religious ritual.
 * 12) Isolate the quatrefoil and identify it (quatrefoil: Old French quatre - four, and foil - leaf).
 * 13) This figure has the shape of a four-leaf clover, considered a sign of good luck.
 * 14) Isolate the oval and identify it (oval: French ovale &lt;Latin ovum&gt; - egg).
 * 15) This figure has the shape of an egg.
 * 16) Isolate the ellipse and identify it (ellipse: Greek elleipsis - an omission or defect &lt;elleipo - to leave out&gt;).
 * 17) What has been left out?
 * 18) Think of the ideal figure, the circle.
 * 19) Place the inset of the ellipse in the circle frame and it is easy to what is missing.
 * 20) This is also the shape of the path that the earth follows around the sun.
 * 21) Isolate the Reuleaux triangle and identify it (curvilinear: Latin curvus - curved, and linear - a line).
 * 22) This triangle has three sides which are curved lines.
 * 23) It is named after a man name Reuleaux who discovered the properties of this shape.
 * 24) He found that a drill bit made in this shape will make square holes.
 * 25) Give three-period lesson and give the reading labels.

Purpose

 * Knowledge of the geometric figures and their relative exact nomenclature.