The question is the base of the triangle, so we use the formula : b²=c²–a²
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[tex] {b}^{2} = \sqrt{c^{2} - {a}^{2} }[/tex]
[tex] {b}^{2} = \sqrt{ {16}^{2} - {8}^{2} } [/tex]
[tex] {b}^{2} = \sqrt{256 - 64} = \sqrt{192} [/tex]
[tex] \sqrt{192} =8 \sqrt{3} [/tex]