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> Let $ABC$ be a triangle where $\angle B$ is a right angle. Extend $AC$ up to point $D$ such that $\angle CBD=30^\circ$. If $AB=CD=1$, find $AC$.
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My approach to this problem is first to try to find some similarity among the triangle, but did not succeed to find any similar triangle. I then try to use some trigonometry to solve the problem, such as the law of sine, but again, did not succeed.

Any hint of solution to this problem would be appreciated.