Find the Length of the Third Side of the Right $\sqrt{39} \approx 1.198$

Multiple Choice

Find the length of the third side of the right triangle. Where appropriate, give both an exact answer and an approximation to three decimal places.
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A) $\sqrt{39} \approx 1.198$
B) $\sqrt{60} \approx 1.435$
C) $\sqrt{18} \approx 4.243$
D) $\sqrt{144} \approx 2.060$