Final answer:
In 'Roller Girl,' Astrid is inspired to take up roller derby after being captivated by a skater named Rainbow Bite and the exciting atmosphere of a live roller derby bout.
Step-by-step explanation:
In the book Roller Girl, Astrid is inspired to take up roller derby after she attends a roller derby bout with her mother. She is fascinated by the tough, confident women she sees skating around the track, particularly her idol, Rainbow Bite. Astrid's journey into the world of roller derby is a central theme of the book, highlighting her personal growth and the lessons she learns about teamwork, friendship, and perseverance.
Hence, in 'Roller Girl,' Astrid finds inspiration to join roller derby sparked by her fascination with a skater named Rainbow Bite and the thrilling atmosphere of a live roller derby match.