Answer:
[tex]8^{2} +U^{2} =17^{2}[/tex]
solve the squared numbers
[tex]8^{2} =64[/tex]
[tex]17^{2} =225[/tex]
[tex]64+U^{2} =225[/tex]
subtract 64 from 289
[tex]U^{2} =225[/tex]
square root 225
[tex]U=[/tex][tex]\sqrt{225}[/tex]
simplify that
[tex]U=[/tex][tex]\sqrt{15^2}[/tex]
[tex]U= 15[/tex]