If △ABC is an isosceles triangles with ∠C = 90° and AC = 5 cm, then AB is:

If △ABC is an isosceles triangles with ∠C = = 90° and AC = 5 cm, then AB is:
[A]5\sqrt{2}cm
[B]2.5 cm
[C]5 cm
[D]10 cm

\mathbf{5\sqrt{2}}cm

AC = BC = 5 cm
∴ AB =\sqrt{AC^{2}+BC^{2}}
= \sqrt{5^{2}+5^{2}} = \sqrt{50} = 5\sqrt{2} cm
Hence option [A] is the right answer.

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