[tex]bc = ac2 + ab2 \\ bc2 = \\ bc = \sqrt{?} [/tex]

Pythagoras

[tex] {a}^{2} + {b}^{2} = {c}^{2} \\ {ac}^{2} + {ab}^{2} = {bc}^{2} \\ \\ {3}^{2} + {4}^{2} = {ba}^{2} \\ \\ 9 + 16 = {bc}^{2} \\ bc = \sqrt{25} \\ bc = 5[/tex]