It is x to the sixth power.
The cube root of the square root is the sixth root. The sixth root of 729 = 3
It is 1.
No, pi is not used to solve a square root problem.
The "sixth square root" is an ambiguous term. The "sixth root" of 126 ... the number which when multiplied by itself 6 times becomes 126 ... is 2.23904 (rounded)
What square root property is essential to solve any radical equation involving square root?
The sixth root of 100,000 is: ± 6.812921