Answer:
Center: (4,8)
Radius: 2.5
Equation: 
Step-by-step explanation:
It was given that; the endpoints of the longest chord on a circle are (4, 5.5) and (4, 10.5).
Note that the longest chord is the diameter;
The midpoint of the ends of the diameter gives us the center;
Use the midpoint formula;
The center is at; 
To find the radius, use the distance formula to find the distance from the center to one of the endpoints.
The distance formula is;
The equation of the circle in standard form is given by;
We substitute the center and the radius into the formula to get;
Answer:
The submarine needs to move up, so the rate the submarine needs to move is positive.
If the perimeters are equal, you can form an equation to find x:
x + x + 12 + x + x + 12 = x + 11 + x + 11 + x + 16
4x + 24 = 3x + 38
- 3x
x + 24 = 38
- 24
x = 14
Now you can substitute the x value into the perimeter:
(4 × 14) + 24
56 + 24 = 80 cm
(3 × 14) + 38
42 + 38 = 80 cm
So the perimeter would be 80 cm.
I hope this helps!
It hits the ground at h=0
0=-16t^2-16t+96
undistribute -16
0=-16(t^2+t-6)
factor
0=-16(t-2)(t+3)
set to zero
0=t-2
2=t
t+3=0
t=-3, nope, we can't have negative time
at t=2, or 2 seconds
5 = what percent of 23
5 = x% of 23
5 = (x/100)*23
5 = 23x/100
5*100 = 23x
23x = 5*100
x = 5*100/23
x = 21.739
5 is ≈ 21.739% of 23
