Deduction 1 - What is the length of the other diagonal?

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Deduction 1 – What is the length of the other diagonal?Given AC = 8 cm To find BD, we use congruency We prove triangles ∆ ABD & ∆ DCA congruent Since ABCD is a rectangle Opposite sides are equal ∴ AB = CD And, all Angles are 90° ∠ A = ∠ D = 90° In ∆ ABD and ∆ DCA AB = CD ∠ A = ∠ D AD = AD ∴ ∆ ABD ≅ ∆ DCA By CPCT (Corresponding Parts of Congruent Triangles) BD = AC Thus, If one diagonal is 8 cm long Other diagonal is also 8 cm long