Posted by
**John** on
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Circles \Gamma_1 and \Gamma_2 intersect at 2 distinct points A and B. A line l through A intersects \Gamma_1 and \Gamma_2 at C and D, respectively. Let M be the midpoint of CD. The line MB intersects \Gamma_1 and \Gamma_2 again at E and F , respectively. If MA=129, MB =156 and MC =182 , what is the value of EF ?