ANSWER
b = 13
EXPLANATION
We want to solve the equation:
[tex]9^2+b^2=15.81^2[/tex]To do this, simplify the equation:
[tex]81+b^2=249.96[/tex]Isolate b:
[tex]\begin{gathered} b^2=249.96-81 \\ b^2=168.96 \\ Find\text{ the square root of boths side:} \\ b=\sqrt[]{168.96} \\ b=13 \end{gathered}[/tex]That is the answer.
