Answer:2.8284.
Step-by-step explanation:
Answer:
May be answer od your question is =
Answer: 8.040328
I don't know but hope it helps
1.
is less than 3.5
2.
is more than 2.1
3. -5.3 is more than -5 
4.
is less than 0.8 repeating
We know in these kind of triangles that have a 90 degrees angle, we can do:

so the first question:

and then:

so , when you want to rationalize , usually you must multiply the irrational factor as 1:

so , now multiply:

in the next question,we know negative numbers in radical don't have any solution so 2 is correct,