Trigo Course and bearign problem :(

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kinuel8091

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Jul 27, 2013
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A ship leaves the port at 12:00 noon heading west with a speed of square root of 3 knots. At 2:00 PM due to a navigational error, the ship turned at a bearing of N 60° W with at speed of 2 knots. How far is the ship from the port at 3:00 PM?

I 1st solved for the distance
d=rt
d=√3 *2
distance from start to the west 2√3

d=rt
d=2*1
d=2
distance from the west point from 2:00pm to the point of 3:00pm

Then what? i don't know what to do next :(

We only need to use the special angles. 60,30,45. :(
 
kinuel8091 said:
A ship leaves the port at 12:00 noon heading west with a speed of square root of 3 knots. At 2:00 PM due to a navigational error, the ship turned at a bearing of N 60° W with at speed of 2 knots. How far is the ship from the port at 3:00 PM?

I 1st solved for the distance
d=rt
d=√3 *2
distance from start to the west 2√3 CORRECT

d=rt
d=2*1
d=2 CORRECT
distance from the west point from 2:00pm to the point of 3:00pm

Then what? i don't know what to do next :(

We only need to use the special angles. 60,30,45. :(
Click to expand...

Do you see when you draw out this triangle that is formed by the ship that you have a 30-60-90 triangle and furthermore you have the lengths of the two legs. You want the length of the hypotenuse. What are the ratios of the sides of a 30-60-90 triangle? Use the ratios to find the hypotenuse and thus your answer. :D
 
srmichael said:
Do you see when you draw out this triangle that is formed by the ship that you have a 30-60-90 triangle and furthermore you have the lengths of the two legs. You want the length of the hypotenuse. What are the ratios of the sides of a 30-60-90 triangle? Use the ratios to find the hypotenuse and thus your answer. :D
Click to expand...
Like this? Help :(

3.jpg
 
kinuel8091 said:
Like this? Help :(

View attachment 3391
Click to expand...
You already have length of 1st leg = 2sqrt(3) West,
and length of green leg = 2.
Since the green leg is the hypotenuse of a 30-60-90° triangle, you can decompose it into West and North components.
Add 2sqrt(3) to the West component to get the total West distance.
Knowing the (x,y) of the red point, the distance you want is the red hypotenuse.
 
DrPhil said:
You already have length of 1st leg = 2sqrt(3) West,
and length of green leg = 2.
Since the green leg is the hypotenuse of a 30-60-90° triangle, you can decompose it into West and North components.
Add 2sqrt(3) to the West component to get the total West distance.
Knowing the (x,y) of the red point, the distance you want is the red hypotenuse.
Click to expand...

3.jpg
Here, I don't get the "you can decompose it into West and North components.
Add 2sqrt(3) to the West component to get the total West distance."
 
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