Answer
F
Work Step by Step
$x=5\csc 38^{\circ}\implies \csc38^{\circ}=\frac{x}{5}$
But $\csc\theta=\frac{\text{hypotenuse}}{\text{opposite side}}$
This implies that $5$ is the length of the opposite side to the $38^{\circ}$ angle and the length of the hypotenuse is $x$. This is the case in triangle F.
