can someone please explain how to find the answer?

Step-by-step explanation:
Given is an right isosceles triangle.
Therefore length of both perpendicular sides would be 2 ft. g represents hypotenuse.
Now by Pythagoras theorem:
[tex]g = \sqrt{ {2}^{2} + {2}^{2} } \\ = \sqrt{2 \times {2}^{2} } \\ = \sqrt{2 \times 4 } \\ = \sqrt{8} \\ \therefore \: g = \sqrt{8} \: ft \\or \: g =2 \sqrt{2} \:ft [/tex]