# Hollow Circle at the edge!

Consider a ring which mass is standard distributed .

The ring is place at one corner of the table as the picture shown above.

What is the minimum ratio of area $$\frac{A}{B}$$ when the ring is just going to fall from the corner?

If the answer can be represented by $$\frac{a\pi -b}{c\pi+d}$$ which $$a,b,c,d$$ is positive integer and the fraction is the simplest form. Then find $$a+b+c+d$$.

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