Answer: 7
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Work Shown:
[tex]a^2 + b^2 = c^2\ \text{ ... pythagorean theorem}\\\\4^2 + x^2 = \left(\sqrt{65}\right)^2\\\\16 + x^2 = 65\\\\x^2 = 65-16\\\\x^2 = 49\\\\x = \sqrt{49} \ \text{ ... only consider the positive root}\\\\x = 7\\\\[/tex]
