Answer: 
which is Choice B
This is the same as writing 
The second "2" is not under or inside the square root.
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Explanation:
Refer to the unit circle below. I've highlighted the angle 45 degrees and its corresponding sine value. It's the y coordinate of the point on the unit circle, for this particular angle.
Therefore, 
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You could alternatively draw out a 45-45-90 triangle. Let x be the leg length and the hypotenuse is 1 unit long. Solve 
for x and you should get 
as the length of each leg.
Then take the ratio of the opposite over hypotenuse to find the same answer mentioned above.
Given:
A pilot can travel 450 miles with the wind in the same amount of time as 360 miles against the wind.
Pilot's speed in still air is 315 miles per hour.
To find:
The speed of the wind.
Solution:
Let the speed of wind be x miles per hour.
Speed with wind = 315+x miles per hour
Speed against wind = 315-x miles per hour
We know that,
According to the question,
Divide both sides by 90.
By cross multiplication, we get
Divide both sides by 9.
Therefore, the speed of wind is 35 miles per hour.
It's a because the form is y-y1=m(x-x1) and of you put the given information in it will be y+1=-(x+10)
