What is the value of y? me will mark brainliest!

To find the value of y:
STEPS:

1) make the equation.

This is the formula you'd use for this one:
     NT^2 = NU(NU+UM)

2)  Using the formula above, substitute using the values provided in the diagram:

   y² = 9(9+3)

3) Simplify on the right side:

   y² = 9(12)
   y² = 108

4) do square root on both sides of the equation to get rid of the y² on the left side:

  √y² = √108

5) Now simplify the square root of 108- break 108 down into smallest possible numbers:

   y = √2x2x3x3x3
 
6) simplify

   y = 2x3√3

   y= 6√3
  
   
So y=6√3- option 2 is correct.

Answer: r=4.5  feetexplanation: radius  r  is half of the diameter  d,⇒r=d2=92=4.5  feetidk i could be wrong