Ariz. Rev. Stat. § 15-447
The state board of education may grant permission to the governing board of a common school district to offer instruction in high school subjects, grades nine through twelve, except that the state board shall not grant permission if the qualified electors of a common school district have voted against the formation of a high school district within the last five years. If the qualified electors of a common school district vote against the formation of a high school district within one year after the state board has granted permission to the governing board to offer instruction in high school subjects, the governing board shall cease to offer instruction in high school subjects at the end of the current year and shall not offer such instruction until such time as the state board has again granted permission in accordance with this section. Enrollment of pupils in grades nine through twelve shall be deemed to be enrollment in high school. For purposes of computing the base support level, the support level weight for high school districts shall be used. Successful completion of a prescribed course of study in grades nine through twelve entitles a pupil to a certificate of high school graduation.
A.R.S. § 15-447