How do I do this one correct?

Applying Pythagorean theorem
[tex]\\ \tt\hookrightarrow c^2=P^2+B^2[/tex]
[tex]\\ \tt\hookrightarrow c^2=20^2+16^2[/tex]
[tex]\\ \tt\hookrightarrow c^2=656[/tex]
[tex]\\ \tt\hookrightarrow c=\sqrt{656}[/tex]
[tex]\\ \tt\hookrightarrow c=25.5[/tex]