2020 AMC 10B Problem 21


In square ABCDABCD , points EE and HH lie on AB\overline{AB} and DA\overline{DA} , respectively, so that AE=AH.AE=AH. Points FF and GG lie on BC\overline{BC} and CD\overline{CD} , respectively, and points II and JJ lie on EH\overline{EH} so that FIEH\overline{FI} \perp \overline{EH} and GJEH\overline{GJ} \perp \overline{EH} . See the figure below. Triangle AEHAEH , quadrilateral BFIEBFIE , quadrilateral DHJGDHJG , and pentagon FCGJIFCGJI each has area 1.1. What is FI2FI^2 ?

(A) 73(B) 842(C) 1+2(D) 742(E) 22\textbf{(A) } \frac{7}{3} \qquad \textbf{(B) } 8-4\sqrt2 \qquad \textbf{(C) } 1+\sqrt2 \qquad \textbf{(D) } \frac{7}{4}\sqrt2 \qquad \textbf{(E) } 2\sqrt2


Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.

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Category: AMC 10B
Points: 4
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