Из круга какого наименьшего радиуса можно вырезать треугольник со сторонами А, В, С?

Private Sub Command1_Click()
Dim a, b, c
Dim p 'полпериметр
Dim S 'площадь треугольника
Dim R 'радиус описанной окр.
a = Val(Text1.Text)
b = Val(Text2.Text)
c = Val(Text3.Text)
If a + b <= c Or a + c <= b Or c + b <= a Then
MsgBox "?"
Exit Sub
End If
p = (a + b + c) / 2
S = Sqr(p * (p - a) * (p - b) * (p - c)) 'ф-ла Герона
R = (a * b * c) / (4 * S)
Label1 = "R = " & R
End Sub

Public Sub T()
Dim a, b, c
Dim R As Single
Dim p, S
a = InputBox("a")
b = InputBox("b")
c = InputBox("c")
p = (a + b + c) / 2 'polyperimetr
S = Sqr(p * (p - a) * (p - b) * (p - c)) ' formula Gerona
R = (a * b * c) / (4 * S) 'radius opisannoy okryzhnosti
MsgBox (R)
End Sub

Function z(Optional a As Double = 1, Optional b As Double = 1, Optional c As Double = 1)
If a > 0 And b > 0 And c > 0 Then
    coa = (b ^ 2 + c ^ 2 - a ^ 2) / (2 * b * c)
    cob = (a ^ 2 + c ^ 2 - b ^ 2) / (2 * a * c)
    coc = (b ^ 2 + a ^ 2 - c ^ 2) / (2 * b * a)
    m = maxx(Abs(coa), Abs(cob), Abs(coc))
    If m < 1 Then
        If coa * cob * coc < 0 Then 'åñëè åñòü òóïîé óãîë òî îäèí èç êîñèíóñîâ îòðèöàòåüëíûé
        z = maxx(a, b, c) / 2
        Else
            p = (a + b + c) / 2 'polyperimetr
            S = Sqr(p * (p - a) * (p - b) * (p - c)) ' formula Gerona
            z = (a * b * c) / (4 * S) 'radius opisannoy okryzhnosti
        End If
    Else
        MsgBox "íå ñóùåñòâóåò!"
        z = False
    End If
Else
    MsgBox "ïëîõàÿ äëèííà ñòîðîí!"
End If
End Function
 
Public Function maxx(a, b, c)
maxx = Switch(a >= b And a >= c, a, b >= a And b >= c, b, c >= b And c >= a, c)
End Function