Lets draw the following picture:
From the figure, we can see that the area of the square on the left is given by

And the area of the square below is

By applying Pytagorean theorem,

we get

which gives

therefore, c is equal to
![c=\sqrt[]{289}](https://img.qammunity.org/2023/formulas/mathematics/college/sk7yeutddd64ph3ck4fgvwmbvf4rxzbspq.png)
and the answer is c = 17.