It’s not a function because the domain (the X) is repeating...
X cannot repeat if you want it to be a function
Answer:
Im not sure but, i would see what each corner is each.
use the Pythagoras theorem method
a squared plus b squared equals c square
Missing: 360 | Must include: 360
look at
https://www.google.com/search?q=x+%3D+4.+5x+%2B23x%5E3+-+360&rlz=1CAJAIV_enUS838&oq=x+%3D+4.+5x+%2B23x%5E3+-+360&aqs=chrome..69i57&sourceid=chrome&ie=UTF-8&safe=active&ssui=on