As shown in the figure, the planes of two congruent squares ABCD and abef intersect AB, m ∈ AC, n ∈ FB, and am = FN

Proof 1: MP ⊥ BC, NQ ⊥ be through M, P and Q are perpendicular feet (as shown in the figure), connecting PQ. ∵ MP ∥ AB, NQ ∥ AB, ∥ MP ∥ NQ. NQ = 22bn = 22cm = MP, ∥ mpqn is parallelogram. ∥ Mn ∥ PQ, PQ ⊂ plane BCE. And Mn ⊄ plane BCE, ∥ Mn ⊉ plane BCE. Proof 2: Mg ∥ BC through M, intersect

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1. It is known that ABCD and abef are two squares and not in the same plane, m and N are the points on the diagonal AC and FB respectively, and am = FN It is suggested that the extension line connecting an and be should be connected to g
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5. As shown in the figure, the diagonal lines AC and BD of rectangular ABCD intersect at point O, EF ⊥ BD at point O, ad at point E, BC at point F, and EF = BF
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9. The quadrilateral ABCD is a rectangle,
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