your driver's licence, or
Australian passport number, or
have someone who is enrolled confirm your identity.
18+ or Proof of Age cards are not accepted.
https://www.aec.gov.au/enrol/
No. Arc length of a circle formula found on page 2 of the General Mathematics formula sheet https://educationstandards.nsw.edu.au/wps/wcm/connect/d1794864-ef77-4a58-9a70-330fdc9714b2/mathematics-general-2-formulae-and-data-sheet-hsc.pdf?MOD=AJPERES&CVID=
Does it have to be HSC questions?