[tex]\text{Apply Pythagorean theorem,}\\ \\~~~~~~~x^2 = 25^2 +75^2\\\\\implies x =\sqrt{25^2 +75^2}\\ \\\implies x = \sqrt{625+5625}\\\\\implies x = \sqrt{6250}\\\\\implies x =\sqrt{625 \times 10}\\\\\implies x = \sqrt{25^2 \times 10}\\\\\implies x = 25\sqrt{10}[/tex]
