Trigonometrina is Trina Riffin's alter-ego. She is Trina's secret nerdy personality that she hides from everyone else behind an alter-ego so that nobody knows that she is secretly a nerd. She was seen in the episode "Math of Kon." In this episode, Corey revealed that she and Trina were the same person, by shooting a guitar pick at the pencil in her hair, revealing her to be Trina.
Trigonometrina is Trina wearing her hair in a bun with a pencil going through it and a pair of darkly colored magenta glasses. She wears a plaid green buttoned shirt with a yellow shirt under it. She also wears brown pants, orange socks, and brown shoes.
Trigonometrina is a nerd who is obsessed with math. She is really good at doing math and she gets along with the other nerds at the school, even Mina.
- Her name is a pun on "trigonometry", a form of mathematics.
- It is unlikely that Trina will ever reprise Trigonometrina after the events of everybody figuring out her secret identity after Corey revealed it to the school.