# Calculate angle of ruler by height raised

If you set a ruler on a table, it will flat with an angle of zero. But if you raise one end up, the angle will change (along with some other things). I'm looking for a function that given the height of the ruler raised what will the angle be.

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$\sin(\theta)=\frac{x}{12}$ so $\theta=\arcsin(\frac{x}{12})$