Let's solve
Using Pythagorean theorem
[tex]\\ \sf\longmapsto H^2=P^2+B^2[/tex]
[tex]\\ \sf\longmapsto c^2=8^2+5^2[/tex]
[tex]\\ \sf\longmapsto c^2=64+25[/tex]
[tex]\\ \sf\longmapsto c^2=89[/tex]
[tex]\\ \sf\longmapsto c=\sqrt{89}[/tex]
[tex]\\ \sf\longmapsto c\approx 9.22[/tex]
