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1962 AMC 12 Question 18

AMC12 · 1962 AMC 12

Question 18

A regular dodecagon ($12$ sides) is inscribed in a circle with radius $r$ inches. The area of the dodecagon, in square inches, is:
  1. $3r^2$
  2. $2r^2$
  3. $\dfrac{3r^2\sqrt3}{4}$
  4. $r^2\sqrt3$
  5. $3r^2\sqrt3$