Some properties of a regular 11-gon
A regular 11-gon is defined by points A, B, C, ..., J, K. Diagonals CE, CF, CG, CH, DF, DK and HK are drawn. Then intersection points L, M, N and O are defined as shown in the figure.
Prove the following statements:
- b=c,
- d=e,
- triangles CLM and CON are congruent,
- a=l (that is, AB=DL).