the answer it four and one sixths
You must factoring the number 192, you will get 192=2^6*3, so you have square root(2^6*3)=2^(6/2)*root(3) applying enhancing property.
Solve the exponent and you get =2^3*root(3)= 8*root(3)
They added it wrong. They added it like this:

When it shouldve been this:

They just added a place marker in all numbers below 100.
1. 10x+6=8-2(x+6)
2. 10x+6=6(x+6)
(distribute the 6)
3. 10x+6=6x+36
(Move the 6x to the other side by subtracting)
4. 4x+6=36
(Move the 6 to the other side by subtracting)
5. 4x=30
(divide)
x=7.5
Hope this helped! :)
Answer:
39
Step-by-step explanation:
found the sides length using pythagorean's theorem, and adding them all together