The figure in the question may be labelled as shown below
There are nine triangle in the upper half of the figure ABFE=ΔAEI,ΔA‌IG,ΔAEG,ΔGEO,ΔGBJ,ΔBFJ,ΔGBF, ΔGOF and ΔGEF. Similarly, there are nine triangles in the lower half figure, i.e. EFCD. There are two more triangles ΔEGH and ΔFGH. Hence, there are a total of 20 triangles.