vb中如何实现自定义坐标后，画一条直线绕其一端点旋转？

建一个Timer1，代码如下。
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Dim i As Single
Private Sub Form_Load()
Timer1.Interval = 10
Scale (-1, 1)-(1, -1)
End Sub

Private Sub Timer1_Timer()
i = i + 0.01
Cls
Line (0, 0)-(Cos(i), Sin(i))
End Sub

Private Sub Form_Load()
Timer1.Interval = 200
End Sub

Private Sub Timer1_Timer()
Cls
Dim x As Single, y As Single
x = 200
y = 200
Scale (-320, 240)-(320, -240)
Line (0, 0)-(x * Cos(i * Pi / 180), y * Sin(i * Pi / 180))
i = i + 15
End Sub