The diagonals of a rhombus meet at right angles. Each bisects the corner angles at its ends. Adjacent angles are supplementary, opposite angles are congruent, and each diagonal creates two isosceles triangles.
a) ∠DAE = 90° - ∠ADE = 90° -57°
∠DAE = 33°
∠ADE = ∠ABD = 57°
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b) ∠CEB = 90° . . . . . the diagonals meet at right angles
