\textbf{130-} Two circles with radii 4 and 5 are externally tangent. From the center of the smaller circle, a common external tangent to the larger circle is drawn. What is the length of this tangent segment?
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(1) $8$ \hfill (2) $4\sqrt{5}$ \hfill (3) $4\sqrt{6}$ \hfill (4) $15$
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