Given the triangle in the attached image.
We want to find the value of x.
Since the triangle is a right-angled triangle, we can apply the Pythagorean theorem to solve for the variable;
![c^2=a^2+b^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/udh1dsx7kwgfauditnn86pp2qhoycm1tvv.png)
For the given triangle;
![\begin{gathered} a=x \\ b=x \\ c=18 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/2f1krvb4zm6g7s6wic4lez9etl1r40sjlp.png)
substituting the values;
![\begin{gathered} 18^2=x^2+x^2 \\ 18^2=2x^2 \\ x^2=(18^2)/(2) \\ x^2=(324)/(2) \\ x^2=162 \\ x=\sqrt[]{162} \\ x=9\sqrt[]{2} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/nwmo6pr9vxc9vwdoqqo3hyupk9445xguph.png)
Therefore, the value of the variable x is;