Known: as shown in the figure, the diagonal AC and BD of diamond ABCD intersect at point O, extend Ba to e, make AE = 12ab, connect OE, extend the extension line of de intersecting CA to F

Known: as shown in the figure, the diagonal AC and BD of diamond ABCD intersect at point O, extend Ba to e, make AE = 12ab, connect OE, extend the extension line of de intersecting CA to F


It is proved that: ∵ rhombic ABCD, ∵ AB = CD, ab ∥ CD, AC ⊥ BD, ∵ AE = 12ab, ∥ AE = 12CD, ab ∥ CD, ∥ FAE ∥ FCD, and the similarity ratio is 1:2, ∵ effd = AECD = 12, ∥ e is the midpoint of DF, ∫ AOD = 90 ° and ∥ OE = 12df