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December 12, 2019, 07:54:16 am

### AuthorTopic: Trigonometry II Worded Problem HELP!  (Read 153 times)

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#### Luke_8064

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##### Trigonometry II Worded Problem HELP!
« on: November 16, 2019, 12:13:46 pm »
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Hi all,

I was just wondering if someone could help me understand the question below (and potentially run through part b for me) :
In a cross-country run, a competitor runs at an average speed of 10m/minute for 20 minutes along a track from the starting point (A) ,directly north to checkpoint B. From checkpoint B they make their way across to checkpoint C, then back to point A. The distance between C and A is 250 m. The bearing of point C from point A has been recorded as 068°T.

(a) Draw a diagram to show the course.
(b) How far is the first leg of the run (i.e. From A to B).
(c) Write down the value of angle A.
(d) Find the distance between the checkpoints B and C.
(e) Determine the bearing of C from B to the nearest degree.

Thanks,
Luke.

PS: Sorry if I am posting in the wrong subject section. I just thought as I am in Foundation Mathematics Methods, I would just post this question here.
« Last Edit: November 16, 2019, 02:28:53 pm by Luke_8064 »

#### Bri MT

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##### Re: Trigonometry II Worded Problem HELP!
« Reply #1 on: November 16, 2019, 12:24:26 pm »
+2
Hey Luke,

Have you been able to draw the diagram for this question? The most crucial part of understanding the wording in the question is recognising the track as a triangle.

For part b in particular, they want you to find the distance using distance = speed x time.
In this case, the units line up nicely (think: metres/minute x minutes = metres) so you don't have to do any annoying conversions.

Hope this helps
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#### Luke_8064

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##### Re: Trigonometry II Worded Problem HELP!
« Reply #2 on: November 16, 2019, 05:13:37 pm »
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Hey Luke,

Have you been able to draw the diagram for this question? The most crucial part of understanding the wording in the question is recognising the track as a triangle.

For part b in particular, they want you to find the distance using distance = speed x time.
In this case, the units line up nicely (think: metres/minute x minutes = metres) so you don't have to do any annoying conversions.

Hope this helps

Hi Bri,

Yes, I did try to draw a diagram however I got confused where the bearing had to go for checkpoint C and A. When I first drew the diagram, I put the 68 degrees at angel C but I thought this was wrong and changed it to angle A. This lead me to be even more confused because in part C of this question it says to declare the what the value of angle A is equal to. This is where I am really confuzzled.

If you could help me understand this part of the problem I would sure appreciate it!
Luke.
« Last Edit: November 16, 2019, 05:21:42 pm by Luke_8064 »

#### RuiAce

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##### Re: Trigonometry II Worded Problem HELP!
« Reply #3 on: November 17, 2019, 10:16:32 am »
+4
Hi Bri,

Yes, I did try to draw a diagram however I got confused where the bearing had to go for checkpoint C and A. When I first drew the diagram, I put the 68 degrees at angel C but I thought this was wrong and changed it to angle A. This lead me to be even more confused because in part C of this question it says to declare the what the value of angle A is equal to. This is where I am really confuzzled.

If you could help me understand this part of the problem I would sure appreciate it!
Luke.
The bearing of the point $C$ from the point $A$ is $68^\circ$. This means that if you draw the northerly direction from $C$, the point $A$ is inclined at $68^\circ$ relative to it. (So your second attempt was the correct one there.)

This is not the same thing as angle $A$. Angle $A$ denotes $\angle BAC$ (or alternatively $\angle CAB$), which is one of the angles in the actual triangle. This is not the same thing as a bearing.
« Last Edit: November 17, 2019, 10:21:37 am by RuiAce »