Find the third side in simplest radical form

Answer:
[tex] 2 \sqrt{71} \: units[/tex]
Step-by-step explanation:
Given is a right angled triangle in which third side is the hypotenuse.
Therefore, by Pythagoras theorem:
[tex]thid \: side = \sqrt{ {15}^{2} + ( \sqrt{59} )^{2} } \\ \\ = \sqrt{225 + 59} \\ \\ = \sqrt{284} \\ \\ = \sqrt{ {2}^{2} \times 71 } \\ \\ = 2 \sqrt{71} \: units[/tex]