# A strange value

Geometry Level 3

In a triangle $$\triangle ABC$$, $$\overline{AC}=6$$, $$\overline{AB}=9$$ and $$\angle C=15°$$. Then, the exact value of $$\overline{BC}$$ can be expressed, in its simplest form, as $$\frac {a \sqrt {b} + a \sqrt {c}}{c}+a \sqrt {d+\sqrt {a}}$$, where $$a$$, $$b$$, $$c$$ and $$d$$ are positive integers. Find $$a+b+c+d$$.

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