2018 AIME I Problems/Problem 8
Let be an equiangular hexagon such that , and . Denote the diameter of the largest circle that fits inside the hexagon. Find .
Solutions
Solution Diagram
[asy] draw((0,0)--(12,20.78)--(24,0)--cycle); draw((1,1.73)--(2,0)); draw((9,15.59)--(15,15.59)); draw((14,0)--(19,8.66)); label("",(9,15.59),NW); label("",(15,15.59),NE); label("",(19,8.66),NE); label("",(14,0),S); label("",(2,0),S); label("",(1,1.73),NW); pair O; O=(11.25,7.36); dot(O); label("",O,SW); draw(Circle(O,6.06)); [/asy] asymptote code for a picture - cooljoseph First of all, draw a good diagram! This is always the key to solving any geometry problem. Once you draw it, realize that . Why? Because since the hexagon is equiangular, we can put an equilateral triangle around it, with side length . Then, if you drew it to scale, notice that the "widest" this circle can be according to is . And it will be obvious that the sides won't be inside the circle, so our answer is .
-expiLnCalc