Pythagorean theorem
[tex]a^2+b^2=c^2[/tex]this is applied for right triangles.
To find one of the sides, the equation can be cleared for a or b.
solve for a.
[tex]\begin{gathered} a^2+b^2=c^2 \\ a^2^{}=c^2-b^2 \\ a=\sqrt[]{c^2-b^2} \end{gathered}[/tex]keep in mind that you are talking aboud distances, meaning that the answer should be a positive integrer.