The Pythagoras theorem says that the sum if a right triangle has side length a, b, and c then
![a^2+b^2=c^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/fdnnfwrccw5g60jmi691r5gcz9ekxf8waa.png)
Now in our case, a = 8, b = ?, and c = 16 in; therefore,
![8^2+b^2=16^2](https://img.qammunity.org/2023/formulas/mathematics/college/ifbclhddpwvxjpk9fiurgqgb3ro3879sjf.png)
![64+b^2=256](https://img.qammunity.org/2023/formulas/mathematics/college/obie580a9gdgz2h5z5w4qhhydi3f5mxsvb.png)
Subtracting 64 from both sides gives
![b^2=256-64](https://img.qammunity.org/2023/formulas/mathematics/college/nh0r7fj24lh8yxfpfj7bkxetfhiwpqljos.png)
![b^2=192](https://img.qammunity.org/2023/formulas/mathematics/college/iuxa6enm17i2437eo9405pfv9fmphcjdh5.png)
Taking the square root of both sides gives
![b=\sqrt[]{192}](https://img.qammunity.org/2023/formulas/mathematics/college/zlztviprfqyukvylyafj3ibh2fa6q8f17r.png)
![b=13.9](https://img.qammunity.org/2023/formulas/mathematics/college/e7fn22mlxqi8fi71q80s4jxqqg10iu0ubx.png)
Hence, the length of the missing side is 13.9.