DefDbl A-Z

Dim crlf$, dr

Private Sub Form_Load()

 Form1.Visible = True

 Text1.Text = ""

 crlf = Chr(13) + Chr(10)

 

 pi = Atn(1) * 4

 dr = pi / 180

 

 cAngle1 = 360 / 30

 

 For v2 = 2 To 30

   cAngle = (v2 - 1) * cAngle1

  ' If cAngle > 180 Then cAngle = 180 - cAngle

   halfAngle = cAngle / 2

   length = 2 * Sin(halfAngle * dr)

   tot = tot + length * length

 Next

 

 Text1.Text = Text1.Text & tot & crlf & " done"

  

End Sub

finds the sum of the squares of the chords from one point to be 60.

FWIW, that makes the total for all the chords 60*30/2 = 900, as each of the 30 vertices shares each of its 60 chords with another vertex and so would be counted twice if not divided by 2.