25.8 that's what I got hope I could help
Answer:
Please look at the attachment for the figure of circle with radius, diameter,circumference labelled.
AB is the diameter
OB and OA are radii
Radius is half of the diameter or in other words diameter is double of radius.
And circumference is the outer line of the circle

Hey This Is The Answer I Got
(x-1)/16=6/12
16*6=12(x-1)
96=12x-12
12x=84
x=7
Hoped I Helped
12.3126 or 12.3..
How I figured this out:
https://www.mathsisfun.com/data/standard-deviation-formulas.html