It is possible to transform a convex polygon with n sides into a polygon with n-1 sides that has the same area.Try the construction following the steps as described below:
1) Draw a polygon with five sides
2) Label its vertexes A, B, C, D,E,F,G anticlockwise
3) Draw , for instance, the diagonal AC and the parallel line r through B to AC
4) Label with F the intersection between r and the extension of CD
5) Prove that the triangle ABC is equivalent to AFC. Now the 5-sides polygon as been transformed in a 4-sides polygon of equivalent area.
6) Following the same steps as previous described, try to transform the 4-sides polygon into a triangle.
7) Finally, prove, using the tool area, that the triangle has the same area of the 5-sides polygon.
8) Explain in a "text box" point 5 and 7.