Answer:(You could also do 45-45-90 special right triangle, which would give you the answer very quickly)
So we have 902+902=c2
Which is 16200=c2
We are finding c, so √16200=c
We can simplify this to √162⋅100 which is 10√162
Then we can simplify this to 10√81⋅2, which is 10⋅9√2
Finally, we multiply the values outside of the root to get our final answer 90√2.
hope it helps !!
Explanation: