Вычисление площади треугольника по координатам трех его вершин - VB

Формулировка задачи:

показывает ошибку, не знаю что не так. программа:

                    Листинг программы
                
 
                        
                          
                    
Private Function pltrkoor(xl As Single, y1 As Single, x2 As Single, y2 As Single, x3 As Single, у3 As Single) As Double 
a= rast(x1, у1, x2, y2) 
b = rast (xl, y1, x3, y3) 
c = rast(x3, y3, x2, y2)
pp  =  (a +  b  +  c) / 2
pltrkoor = (pp * (pp - a) * (pp - b) * (pp – c)) ^ 0.5 
End Function
Private Function rast(xn As Single, yn As Single, xk As Single, yk As Single) As Single 
rast = ((xk - xn) ^ 2 + (yk - yn) ^ 2) ^ 0.5
End Function
 
Private Sub Command1_Click()
Dim xa As Single, ya As Single
Dim xb As Single, yb As Single
Dim xc As Single, yc As Single
Picture1.Cls
xa = Val(Text1)
ya = Val(Text2)
xb = Val(Text3)
yb = Val(Text4)
xc = Val(Text5)
yc = Val(Text6)
s = pltrkoor(xa, ya, xb, yb, xc, yc) 
Picture1.Print Format(s, “#.00”) 
End Sub

Решение задачи: «Вычисление площади треугольника по координатам трех его вершин»

textual
                            Листинг программы 
                        
 
                        
                          
                    
Option Explicit
Private Function pltrkoor(x1 As Single, y1 As Single, x2 As Single, y2 As Single, x3 As Single, y3 As Single) As Double
Dim a As Single, b As Single, c As Single, pp As Double
    a = rast(x1, y1, x2, y2)
    b = rast(x1, y1, x3, y3)
    c = rast(x3, y3, x2, y2)
    pp = (a + b + c) / 2
    pltrkoor = (pp * (pp - a) * (pp - b) * (pp - c)) ^ 0.5
End Function
Private Function rast(xn As Single, yn As Single, xk As Single, yk As Single) As Single
    rast = ((xk - xn) ^ 2 + (yk - yn) ^ 2) ^ 0.5
End Function
 
Private Sub Command1_Click()
Dim xa As Single, ya As Single
Dim xb As Single, yb As Single
Dim xc As Single, yc As Single
Dim s As Double
    Picture1.Cls
    xa = Val(Text1)
    ya = Val(Text2)
    xb = Val(Text3)
    yb = Val(Text4)
    xc = Val(Text5)
    yc = Val(Text6)
    s = pltrkoor(xa, ya, xb, yb, xc, yc)
    Picture1.Print Format(s, "0.00")
End Sub