Area=pi times radius^2 so
if area=4pi=pi times r^2
4 times pi=r^2 times pi
divide both sdies by pi
4=r^2
square root
2=radius since legnth cannot be negative
radius=1/2 diamters
2 radius=diameter
2(2)=diameter=4
diameter=4
100 * pi = pi * r^2
Pi cancels on both sides of the equation
So... 100= r^2
= radius is 10
V = a²h/3
Plugging values in we get 8.67X10^7, or 86,700,000
The slope of <em>y</em> = 2<em>x</em> - 5 is 2. Parallel lines have the same slope, so the slope of the line through the given points <em>A</em> and <em>B</em> is also 2. This means
(8 - 4) / (6 - <em>n</em>) = 2
Solve for <em>n</em> :
4 / (6 - <em>n</em>) = 2
4/2 = 6 - <em>n</em>
2 = 6 - <em>n</em>
<em>n</em> = 6 - 2
<em>n</em> = 4
In solving this problem we can consider Earth to be a sphere. When we have a circle, then we can use this formula to find arc length:

Where:
L= arc length (in this problem it is disance we need to travel)
R = radius of circle (in this problem it is equal to a radius of Earth)
C = angle we need to pass
We are told that two cities lie halfway around the world. If we fly to west this means angle is 180°.
This gives an arc length of:

If we want to fly to north we need to go to 90° northern latidtude and then back to 17° latitude. This means angle is:
C=2*(90-17)=2*73°=146°
This gives an arc length of:

We can see that flying north is shorter. It is shorter by:
12440.71 miles - 10090.8 miles = 2349.91 miles