Hello!The answer is: [tex]tan(x)=\frac{e}{f}[/tex]Why?Since there is a rectangle, it means that there are two right triangles, we can use the second triangle dimensions in order to find the tangent of the angle "x".[tex]tan(x)=\frac{Opposite}{Adjacent}= \frac{e}{f}[/tex]Where:[tex]e=Opposite\\f=Adjacent\\g=Hypotenuse[/tex]We can also determine the sine and cosine of the angle "x"[tex]sin(x)=\frac{Opposite}{Hypotenuse}=\frac{e}{g}\\\\cos(x)=\frac{Adjacent}{Hypotenuse}=\frac{f}{g}[/tex]Have a nice day!