First of all it is spelled trichinella. Trichinella is the genus of parasitic roundworms of the phylum Nematoda that cause trichinosis. Members of this genus are often called trichinella.
you take the length of the trichenella and you multiply it but its length and that's it.
Nematodes are in the Phylum Nematoda, which should be no surprise. The name means roundworms and includes worms such as, the ascaris, hookworms, pinworms, and trichenella.