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2020 AMC 12B Question 18

AMC12 · 2020 AMC 12B

Question 18

In square $ABCD,$ points $E$ and $H$ lie on $\overline{AB}$ and $\overline{DA},$ respectively, so that $AE = AH.$ Points $F$ and $G$ lie on $\overline{BC}$ and $\overline{CD},$ respectively, and points $I$ and $J$ lie on $\overline{EH}$ so that $\overline{FI} \perp \overline{EH}$ and $\overline{GJ} \perp \overline{EH}.$ See the figure below. Triangle $AEH,$ quadrilateral $BFIE,$ quadrilateral $DHJG,$ and pentagon $FCGJI$ each has area $1.$ What is $FI^2?$

Question illustration
  1. $\dfrac73$
  2. $8 - 4\sqrt{2}$
  3. $1 + \sqrt{2}$
  4. $\dfrac74 \sqrt{2}$
  5. $2\sqrt{2}$