Answer :
Using the triangle sum theorem:
[tex]\begin{gathered} \angle U+\angle V+\angle W=180 \\ 90+51+\angle W=180 \\ So\colon \\ \angle W=180-90-51 \\ \angle W=39 \end{gathered}[/tex]Using the triangle sum theorem:
[tex]\begin{gathered} \angle U+\angle V+\angle W=180 \\ 90+51+\angle W=180 \\ So\colon \\ \angle W=180-90-51 \\ \angle W=39 \end{gathered}[/tex]