I need help I’m trying to make a project that calculates pi but it’s not going to well

I am trying to make a project that uses Archimedes method of inscribing polygons within circles to calculate pi but it’s not going to well. I think I might need to learn trigonometry cause’ I am in math 1 in 8th and we haven’t learned it but I don’t really have the time. Basically what’s going on right now is that the calculations for pi keep on reaching 90 and I don’t know what I am doing wrong here is my code:

init = function()
  //n represents the number of sides
  //nl represents the length of each side
  nl = 200
  //na represents the angle of each side
  //na = 90
  
  //p represents the perimeter of the polygon
  p = poly.n * 2 * 50*sin(180/poly.n)
  //pi represents the 
  pi = p/200
  poly.poly_init_()
  //screen.drawRect(0,0,200,200,"rgb(255,255,255)")
end
update = function()
  p = poly.n * 2 * 50*sin(180/poly.n)
  pi = p/200
  nl = p/poly.n
end
poly = class
  n = 4
  poly_init_ = function()
    na = 90
  end
  incSides = function()
    n = n*2
  end
  val = function(int)
    if int == 1 then
      return pi
      print(2)
    end
  end
  /*updatePoly = function()
    //na = 360/n
    //nl = 200*sin(180/n)
  end*/
  //update = function()
    //break
 // end
end
draw = function()
  if touch.touching and touch.y >-180 and touch.y < 180 and touch.x >-180 and touch.x <180 or touch.press then
    poly.incSides()
  end
  poly.incSides()
  update()
  //poly.updatePoly()
  print(poly.val(1) + " pi " + poly.n + " sides " + nl + " sidelength")
  screen.drawRound(0,0,200,200,"rgb(255, 255, 255)")
end