Complex sentence: It is a comprehensive public high school with approximately 1,310 students in grades 9-12, serving the west side of Petaluma and many of the rural areas that surround the city in both Sonoma County and Marin County.
Split into simpler sentences: It is a comprehensive public high school serving approximately 1,310 students in grades 9-12. It serves the west side of Petaluma and many of the rural areas that surround the city in both Sonoma County and Marin County.