It is 780.99999     sorry if i'm incorrect 
        
             
        
        
        
Answer: the rate of speed for train A is 66 miles per hour.
Step-by-step explanation:
Let x represent the speed of train B.
2 trains leave the station at the same time. Train A is traveling 16 miles per hour slower than train B. This means that the speed of train A would be x - 16 miles per hour.
The two trains are 720 miles apart after 4 hours. It means that both trains traveled a total distance of 720 miles in 4 hours.
Distance = speed × time
Distance travelled by train A after 4 hours is 
4(x - 16) = 4x - 64
Distance travelled by train B after 4 hours is 
4 × x = 4x 
Since the total distance travelled by both trains is 720 miles, then
4x - 64 + 4x = 720
8x = 720 - 64 = 656
x = 656/8 = 82 miles per hour
The speed of train A would be 
82 - 16 = 66 miles per hour.
 
        
             
        
        
        
Answer:
(x + 4)^2 + (y - 8)^2 = 81
or
(x + 4)^2 + (y - 8)^2 = 9^2 depending on how your teacher wants it written.
Step-by-step explanation:
The standard form for a circle is 
(x + h)^2 + (y + k)^2 = r^2
r is the radius. 
You are given the diameter
r = d/2
r = 18/2
r = 9
So you already have the right hand side of the equation
(x + h)^2 + (y + k)^2 = 9*2
(x + h)^2 + (y + k)^2 = 81
You basically have h and k as well. They come from the center point.
h = 4
k = - 8
So the equation of the circle (and the answer) is
(x + 4)^2 + (y - 8)^2 = 81
One question remains. Why do the x and y values change signs? If you know what the distance formula is, then what you are finding is the distance r of all points on the circle from the center of the circle.
It is the distance formula that is actually the formula for the circle.
 
        
             
        
        
        
Answer:
m∠J = m∠Z = 46°
Step-by-step explanation:
m∠J = m∠Z = 46°