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Bearing question!!!

The diagram shows the position of three boats, P, Q and R. Boat Q is 7 km from boat P on a
bearing of 327°. Boat R is 15 km from boat P on a bearing of 041°.
(a) Find the distance between boats Q and R to 1 decimal place.
(5)
(b) Find the 3 figure bearing of boat R from boat Q.
(5)
(10 marks)
(edited 5 years ago)

Reply 1

Original post by Sidd1
The diagram shows the position of three boats, P, Q and R. Boat Q is 7 km from boat P on a
bearing of 327°. Boat R is 15 km from boat P on a bearing of 041°.
(a) Find the distance between boats Q and R to 1 decimal place.
(5)
(b) Find the 3 figure bearing of boat R from boat Q.
(5)
(10 marks)

What are you stuck with?

Reply 2

Original post by Sidd1
The diagram shows the position of three boats, P, Q and R. Boat Q is 7 km from boat P on a
bearing of 327°. Boat R is 15 km from boat P on a bearing of 041°.
(a) Find the distance between boats Q and R to 1 decimal place.
(5)
(b) Find the 3 figure bearing of boat R from boat Q.
(5)
(10 marks)

Put the angles you know onto the diagram. You then know angle QPR and can use the cosine rule to do part (a)

Reply 3

Original post by Muttley79
Put the angles you know onto the diagram. You then know angle QPR and can use the cosine rule to do part (a)

I'm struggling with labelling the angles... so does 327 degrees go on bearing from Q and 41 degrees on the bearing from R? I know P is 74 degrees but I can't figure out how

Reply 4

Original post by Sidd1
I'm struggling with labelling the angles... so does 327 degrees go on bearing from Q and 41 degrees on the bearing from R? I know P is 74 degrees but I can't figure out how

The 41 is the angle between PR and the North line and the other 'bit' of that angle is 360 - 327 [the 327 is the angle clockwise from north to the line PQ].

Reply 5

Original post by Muttley79
The 41 is the angle between PR and the North line and the other 'bit' of that angle is 360 - 327 [the 327 is the angle clockwise from north to the line PQ].

Oh okay makes sense :smile:

Reply 6

Original post by Sidd1
Oh okay makes sense :smile:

For part b I used the sine rule and got 78.8 degrees but that isn't the answer .. they did 180 degrees - 78.8 - 33??

Reply 7

Original post by Sidd1
For part b I used the sine rule and got 78.8 degrees but that isn't the answer .. they did 180 degrees - 78.8 - 33??

You need the bearing ... this is the angle between the North line at Q and the line QR.

Reply 8

Original post by Sidd1
The diagram shows the position of three boats, P, Q and R. Boat Q is 7 km from boat P on a
bearing of 327°. Boat R is 15 km from boat P on a bearing of 041°.
(a) Find the distance between boats Q and R to 1 decimal place.
(5)
(b) Find the 3 figure bearing of boat R from boat Q.
(5)
(10 marks)


I got 027 for part B, can someone let me know if this is correct?, Thanks in advance. I will give you a rep too so please lemme know lol ty

Im getting a feeling i got the bearing for the wrong one.
(edited 2 years ago)

Reply 9

Original post by HashMash
I got 027 for part B, can someone let me know if this is correct?, Thanks in advance. I will give you a rep too so please lemme know lol ty

Im getting a feeling i got the bearing for the wrong one.


im p sure youre correct cause i got 027 too :smile:

Reply 10

Original post by jeanboy5
im p sure youre correct cause i got 027 too :smile:

Hello, I got 068° for the bearing. I did 180-33 to get 147° which is the angle from the north line to QP. I then found out andle RQP with Sin rule --> sin74 / 14.7 = sin theta / 15, to which I got 78.77°. I then did 147-78.77 to get the bearing, which was 68.23°, however since it's a bearing and I rounded it to 068°.

If you've noticed anything wrong with what I did please let me know, as you both seem to have gotten the same answer!

Reply 11

Original post by Tealeaf5
Hello, I got 068° for the bearing. I did 180-33 to get 147° which is the angle from the north line to QP. I then found out andle RQP with Sin rule --> sin74 / 14.7 = sin theta / 15, to which I got 78.77°. I then did 147-78.77 to get the bearing, which was 68.23°, however since it's a bearing and I rounded it to 068°.
If you've noticed anything wrong with what I did please let me know, as you both seem to have gotten the same answer!

I got this answer too. And for part a i got 14.7km

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