If this is supposed to be a riddle, it's not a very good one. The square root of the number whose square root is two is, obviously, two.
The square root of four is two. Therefore, 20.84 plus 2 is 22.84.
five
12.937254
The square root of two times the square root of two equals two
No. For example, the square root of two plus (minus the square root of two) = 0, which is not an irrational number.
Two times the square root of three plus five times the square root of three plus four times the square root of three equals eleven times the square root of three.
plus (+) 70 and minus (-) 70
You can. Just add the numbers together, and find their square root. One plus three is four; the square root of the sum is two.
14
26
(7*sqrt(2))/2 (Seven time the square root of 2, divided by two)