
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
In triangle $ABC$, let $a$, $b$, and $c$ be the lengths of the sides opposite angles $A$, $B$, and $C$ respectively. It is given that $\frac {\sin B}{2\sin A-\sin C}= \frac {1}{2\cos C}$.  
(I) Find the measure of angle $B$.  
(II) If $a=1$ and $b= \sqrt {7}$, find the area of triangle $ABC$.

Present the answer in LaTex format: \boxed{Your answer}
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