
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 the Cartesian coordinate system $xOy$, point $A(4,0)$ is given. The orthogonal projection of the moving point $M$ on the $y$-axis is point $N$, and it satisfies that line $MO$ is perpendicular to $NA$.  
(Ⅰ) Find the equation of the trajectory $C$ of the moving point $M$;  
(Ⅱ) When $\angle MOA= \frac {\pi}{6}$, find the equation of line $NA$.

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