After a little review, we are going to begin with some 3rd ESO content: regular polygons with a given side: triangle, square, pentagon, hexagon, heptagon, octagon and nonagon.
Although I will give you some notes, you can see two interesting resources (in Spanish):
- Construcciones de dibujo técnico de Javier de Prada, where you can find polygons with the circumference or in “polígonos II” with a given side (dado el lado):
Remember: polygons obey different symmetries depending on the number of their sides:
- If the number of sides is EVEN, the polygon has a radial symmetry. Its radial centre is the centre of the circumference around it.
- If the number of sides is ODD, the polygon has an axial symmetry. The vertices are opposite of the middle point of the opposite side.
Surf and practise on Ritmo y Simetría en la composición plástica by Mª Luisa Bermejo, winner of the contest Materiales Curriculares 2005. You can explore and have fun with this resource!