[tex]\bf 2\pi \sqrt{\cfrac{\quad \frac{9}{2}\quad }{32}}\implies 2\pi \sqrt{\cfrac{\quad \frac{9}{2}\quad }{\frac{32}{1}}}\implies 2\pi \sqrt{\cfrac{9}{2}\cdot \cfrac{1}{32}}\implies 2\pi \sqrt{\cfrac{9}{64}}
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2\pi \sqrt{\cfrac{3^2}{8^2}}\implies 2\pi \cdot \cfrac{3}{8}\implies \cfrac{3\pi }{4}[/tex]
