Hello, I'm glad to answer your question. 22. Analysis: (1) quadrilateral BE'FE is a square. Reason: ∵ As can be seen from the rotation: ∴∠ e' = ∠ AEB = 90. ∴∠EBE'=90 .∠∠AE b+∠feb = 90，∴∠ feb = 90。 A quadrilateral is a rectangle. From the rotation, we can know ∴ yes. A quadrilateral is a square. (3)√ 17 。