The length of a tangent from an external point to a circle is 5โ3 unit. If radius of the circle is 5 units, then the distance of the point from the circle is
$$\because$$ AB is a tangent to circle at B,
$$\therefore \angle{OBA}=90$$
In $$\triangle{AOB}$$,
$$AO^{2}=OB^{2}+AB^{2}$$
$$AO^{2}=5^{2}+(5\sqrt{3})^{2}$$
$$AO=10 cm$$
Hence, Option A is correct.
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