Help with GUI and Trigonometry

[goldenstein64 (Shoop)]

local radius = self.Joystick.Parent.Size.X.Offset / 2

local pos = Vector2.new(
    self.Joystick.Position.X.Offset,
    self.Joystick.Position.Y.Offset
)
if pos.Magnitude > radius then
    pos = pos.Unit * radius
end

self.Joystick.Position = UDim2.new(
    0.5,
    pos.X,
    0.5,
    pos.Y
)