Using pythagoras theorem
[tex]\begin{gathered} Hyp^2\text{ = opp}^2+adj^2 \\ x^2\text{ = (2}\sqrt[]{6)^2}+5^2 \\ x^2\text{ = 4(6) + 25} \\ x^2=24^{}+25 \\ x^2\text{ = 49} \\ x\text{ = }\sqrt[]{49} \\ x\text{ = 7} \end{gathered}[/tex]
Hence the length of the third side = 7
