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2021 AMC 10D Question 18

AMC10 · 2021 AMC 10D

Question 18

Three identical square sheets of paper each with side length $6$ are stacked on top of each other. The middle sheet is rotated clockwise $30^\circ$ about its center and the top sheet is rotated clockwise $60^\circ$ about its center, resulting in the $24$-sided polygon shown in the figure below.

The area of this polygon can be expressed in the form $a-b\sqrt{c},$ where $a,$ $b,$ and $c$ are positive integers, and $c$ is not divisible by the square of any prime. What is $a+b+c?$

Question illustration
  1. $ 75 $
  2. $ 93 $
  3. $ 96 $
  4. $ 129 $
  5. $ 147 $