Answer
$T=2\pi\sqrt{\dfrac{l}{32}}$
Work Step by Step
$y$ varies $\bf{directly}$ with $x,$ or $y$ is directly proportional to $x$,
if there is a nonzero number $k$ such that$ \ \ y=kx.$
The number $k$ is called the constant of proportionality.
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Here, $T=k\sqrt{l},$
Given that $k=\displaystyle \frac{2\pi}{\sqrt{32}}$, this becomes
$T=\displaystyle \frac{2\pi}{\sqrt{32}}\cdot\sqrt{l}.$
or
$T=2\pi\sqrt{\dfrac{l}{32}}$
