Athena, the goddess of wisdom and war, appears in just about every Greek hero myth. She's kind of a hero groupie. Athena was Odysseus' special divine friend and also provided key advice and assistance to Heracles, Jason, and, of course, Perseus.
Really, where would Perseus be without Athena? Probably hanging out the in the Gorgons' cave – as a statue. Athena, along with Hermes, guides the young hero to the Graeae, where he gets information that leads him to the Nymphai, who provide him with essential magical tools (Hades' helmet of invisibility, Hermes' winged shoes, and the kibisis). Athena also warns Perseus to only look at Medusa through the reflection in his shiny shield. That clever tip definitely saved his life. Perseus shows his appreciation for Athena's help by giving her Medusa's head after he's finished using it.
But why does Athena help Perseus? That's a good question. It could be that:
Why do you think Athena helped Perseus out?
For more on the patron goddess of heroes, click here.