As we know that sum of three angles of triangle is 180º.
[tex]\blue\star[/tex]we have
[tex] angle \: a + angle \: b+ angle \: c= 180 \\ [/tex]
[tex]a + 45 + 90 = 180 \\ a = 180 - 135 \\ a = 45[/tex]
[tex]\blue\star[/tex] The angles a and c are equal so,
- cb = ab. [ sides opp to equal angles are equal]
so x is also 16
[tex]\blue\star[/tex]Now we have two side we can easily find the third side by P.G.T
- [tex]{AC}^{2}[/tex] = [tex]{BC}^{2}[/tex] + [tex]{AB}^{2}[/tex]
- [tex]{AC}^{2}[/tex] = [tex]{16}^{2}[/tex] + [tex]{16}^{2}[/tex]
- {AC}= [tex]\sqrt{512}[/tex]
so the r is root 512 and x is 16.
Hope it helpa