We will have the following:
[tex]A=(\frac{x}{2})\cdot r^2\Rightarrow120\pi=(\frac{x}{2})(24)^2[/tex][tex]\Rightarrow\frac{x}{2}=\frac{5\pi}{24}\Rightarrow x=\frac{5\pi}{12}[/tex][tex]\Rightarrow x\approx1.31[/tex]So, the value of x is approximately 1.31.