Respuesta :

D is the answer. square root of 64 is 8

By rational it means that which number can be expressed as a fraction, let's simplify and check each one.

Sqrt20=2*sqrt5

sqrt 5 is irrational

sqrt32=4sqrt2

sqrt2 is irrational

sqrt45=3sqrt5

sqrt5 is irrational

sqrt64=8

8 is rational!

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