Presentation of the Materials: Triangles

Age
6-9.

Materials

 * Insets of the fractional parts of a triangle
 * Geometry charts... triangle 1,2,3,4

Presentation

 * 1) Bring out the four insets.
 * 2) Identify the whole triangle: equilateral, whole, unit.
 * 3) Identify the others in the same way as before: the number of equal parts, how they were formed, the value of each resulting piece.
 * 4) The same triangle was divided into two equal parts by the height.
 * 5) Each has the value of 1/2.
 * 6) The same triangle was divided into three equal parts by the angle bisectors extending to the point of intersection.
 * 7) Each has the value of 1/3.
 * 8) The same triangle was divided into four equal parts by finding the midpoints of the sides and joining them.
 * 9) Each has the value of 1/4.
 * 10) Classify the triangles which have been formed: 1/2 - right-angled scalene triangle; 1/3 - obtuse-angled isosceles triangle; 1/4 - equilateral triangle. show chart 1.
 * 11) Examine the relationship between the lines of the fractional triangles and the whole.
 * 12) Show charts 2,3 and 4.

Variation
The child may construct his own charts.