how do i find the missing sides in these angles

Solution:
Given the triangles;
Using Pythagorean Theorem;
(a)
[tex]\begin{gathered} h^2=o^2+a^2 \\ \\ h=hypotenuse,o=opposite,a=adjacent \end{gathered}[/tex]Thus;
[tex]\begin{gathered} x^2=12^2+5^2 \\ \\ x^2=144+25 \\ \\ x^2=169 \\ \\ x=\sqrt{169} \\ \\ x=13 \end{gathered}[/tex](b)
[tex]\begin{gathered} 4.3^2=1.7^2+x^2 \\ \\ x^2=18.49-2.89 \\ \\ x^2=15.6 \\ \\ x=\sqrt{15.6} \\ \\ x=3.9 \end{gathered}[/tex]