Option Explicit
Public Const DegreeToRadian As Single = 0.0174532925
 
Sub main()
 
    MsgBox DegreeToRadian * Engine_GetAngle(50, 22, 67, 33)
 
End Sub
 
Public Function Engine_GetAngle(ByVal CenterX As Integer, ByVal CenterY As Integer, ByVal TargetX As Integer, ByVal TargetY As Integer) As Single
 
Dim SideA As Single
Dim SideC As Single
 
    On Error GoTo ErrOut
 
    'Check for horizontal lines (90 or 270 degrees)
    If CenterY = TargetY Then
 
        'Check for going right (90 degrees)
        If CenterX < TargetX Then
            Engine_GetAngle = 90
 
            'Check for going left (270 degrees)
        Else
            Engine_GetAngle = 270
        End If
 
        'Exit the function
        Exit Function
 
    End If
 
    'Check for horizontal lines (360 or 180 degrees)
    If CenterX = TargetX Then
 
        'Check for going up (360 degrees)
        If CenterY > TargetY Then
            Engine_GetAngle = 360
 
            'Check for going down (180 degrees)
        Else
            Engine_GetAngle = 180
        End If
 
        'Exit the function
        Exit Function
 
    End If
 
    'Calculate Side C
    SideC = Sqr(Abs(TargetX - CenterX) ^ 2 + Abs(TargetY - CenterY) ^ 2)
 
    'Side B = CenterY
 
    'Calculate Side A
    SideA = Sqr(Abs(TargetX - CenterX) ^ 2 + TargetY ^ 2)
 
    'Calculate the angle
    Engine_GetAngle = (SideA ^ 2 - CenterY ^ 2 - SideC ^ 2) / (CenterY * SideC * -2)
    Engine_GetAngle = (Atn(-Engine_GetAngle / Sqr(-Engine_GetAngle * Engine_GetAngle + 1)) + 1.5708) * 57.29583
 
    'If the angle is >180, subtract from 360
    If TargetX < CenterX Then Engine_GetAngle = 360 - Engine_GetAngle
 
    'Exit function
 
Exit Function
 
    'Check for error
ErrOut:
 
    'Return a 0 saying there was an error
    Engine_GetAngle = 0
 
Exit Function
 
End Function