Constructive Triangles: Third Box
Box 3 -
- Twelve blue right-angled scalene triangles with no black lines. The angles measure 30, 60, and 90 degrees.
- Isolate one triangle.
- Ask the child to identify each of the angles, and the biggest and smallest angles.
- This angle which is neither smallest nor biggest we can call the medium angle.
- The child names each angle: smallest angle, medium angle, biggest angle.
- First star: Let's unite all the triangles by their smallest angle.
- The directress positions a few and allows the child to continue.
- How many points does this star have? Twelve.
- With all of the triangles at our disposal, we can make only one star with twelve points.
- Second star: Let's unite all the triangles by the medium angles.
- How many points does this star have? Six.
- Try to make another star with the triangles that are left.
- With all the triangles at our disposal, we can make two stars with six points.
- Third star: Let's unite all of the triangles by the largest angle.
- How many points does this star have? Four.
- This symbol is very famous; it is the star of Saint Brigid, the patron saint of Ireland.
- Try to make another star like this.
- With all the triangles at our disposal, we can make three stars with four points.
Control Of Error
Points Of Interest
Use of the triangle as a constructor to indirectly demonstrate the following:
- 30o x 12 triangles = 360o
- 60o x 6 triangles = 360o
- 90o x 4 triangles = 360o
- 360o / 30o = 12 triangles
- 360o / 60o = 6 triangles
- 360o / 90o = 4 triangles
- 360o / 12 triangles = 30o
- 360o / 6 triangles = 60o
- 360o / 4 triangles = 90o