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GiM at Yale 2021 Mathathon R6: oops no flavortext

Source:

February 28, 2021
Yalecollege

Problem Statement

16. Suppose trapezoid JANEJANE is inscribed in a circle of radius 2525 such that the center of the circle lies inside the trapezoid. If the two bases of JANEJANE have side lengths 1414 and 3030 and the average of the lengths of the two legs is m\sqrt{m}, what is mm?
17. What is the radius of the circle tangent to the xx-axis, the line y=3xy=\sqrt{3}x, and the circle (x103)2+(y10)2=25(x-10\sqrt{3})^2+(y-10)^2=25?
18. Find the smallest positive integer nn such that 3n39n2+5n153n^3-9n^2+5n-15 is divisible by 121121 but not 22.