[tex] \implies \sqrt{ \dfrac{36}{169} } [/tex]
[tex] \implies \sqrt{ \dfrac{6 \times 6}{13 \times 13} } [/tex]
[tex] \implies \sqrt{ \dfrac{ {6}^{2} }{ {13}^{2} } } [/tex]
[tex] \implies \sqrt{ \left(\dfrac{ {6} }{ {13} } \right)^{2} } [/tex]
[tex] \implies {\left(\dfrac{ {6} }{ {13} } \right)^{2 \times }}^{ \frac{1}{2} } [/tex]
[tex] \implies \left(\dfrac{ {6} }{ {13} } \right)[/tex]
This is your answer.
