Answer:
2.0
Step-by-step explanation:
Couldn't really understnd what you wrote but I'll assume it's the standard deviation of a fair, 7-sided die
The standard deviation is just the square root of the variance (which is just the second moment minus the first moment squared)
The first moment (AKA the average is..)

The second moment is..


Answer:
8ft
Step-by-step explanation:
Circumference of a circle equation; πd or2πr
16π = 2πr you can then divide both sides by π
16 = 2r then you can divide both sides by 2
8 = r
Divide the long leg by the square root of 3 to find the short leg. Double that figure to find the hypotenuse.
3/4(x+21) = 10.5
0.75x+15.75 = 10.5
0.75x = -5.25
x = -7
Hope it helps : )