Answer
$x^{o} \approx 125.1^{o}$
Work Step by Step
Apply law of cosines $f^2=d^2+e^2-2de \cos F$
Need to solve for $F =x^{o}$
$2de \cos x^{o}=d^2+e^2-f^2$
This implies $x^{o}=\cos^{-1}(\dfrac{d^2+e^2-f^2}{2de})$
Plug the given values to obtain:
$x^{o}=\cos^{-1}(\dfrac{(16)^2+(20)^2-(32)^2}{2 \times 16 \times 20})$
$x^{o}=\cos^{-1}(\dfrac{-368}{640})$
In order to calculate the value, we will use calculator in degree mode.
$x^{o} \approx 125.1^{o}$
