$\frac{3}{4}$
$\frac{2}{3}$
$\frac{3}{5}$
$\frac{5}{6}$

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The symmetry suggests that the point inside is actually the square centre. Then we can say: (1-x)

1+ (x-1/2)/2 = 1/3 or (x+1/2)1/2*1/2 =1/3. Either way, x = 5/6