# How to I do these trigonometry question?

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#1
Three points A, B and C lie on a level plane.
B is 7 km from A on a bearing of 030°.
C is 5 km from B on a bearing of 280°.
i) Find the distance AC.
ii) Find the bearing of A from C
iii) Find the area of triangle ABC
(Give all answers correct to 3 significant figures)
I think number ii) is incorrect? Can someone please explain how to do these questions I have no idea.
0
5 years ago
#2
sine and cosine rule is relevant
you just need to choose which one is relevant to this question
Spoiler:
Show
but i am not sure SURE
0
5 years ago
#3
(Original post by fatima1998)
sine and cosine rule is relevant
you just need to choose which one is relevant to this question
Spoiler:
Show
but i am not sure SURE
thanks ❤•.¸✿¸.• 𝓢𝓽𝓾𝓭𝔂 ℋ𝒆𝓵𝓹𝒆𝓻 •.¸✿¸.•❤
0
5 years ago
#4
(Original post by ❤✿𝓢𝓽𝓾𝓭𝔂 ℋ𝒆𝓵𝓹𝒆𝓻✿❤)
thanks ❤•.¸✿¸.• 𝓢𝓽𝓾𝓭𝔂 ℋ𝒆𝓵𝓹𝒆𝓻 •.¸✿¸.•❤
0
5 years ago
#5
(Original post by Marmite170899)
Three points A, B and C lie on a level plane.
B is 7 km from A on a bearing of 030°.
C is 5 km from B on a bearing of 280°.
i) Find the distance AC.
ii) Find the bearing of A from C
iii) Find the area of triangle ABC
(Give all answers correct to 3 significant figures)
I think number ii) is incorrect? Can someone please explain how to do these questions I have no idea.
look at your diagram again, you have done a bearing of 060

also from B to C, that isn't how you do the bearing. Always start looking north (ie up to page) and go clockwise

Edit: re-reading this it sounds very rude, i didn't mean that way, sorry
0
5 years ago
#6
too late ...
0
#7
(Original post by DylanJ42)
look at your diagram again, you have done a bearing of 060

also from B to C, that isn't how you do the bearing. Always start looking north (ie up to page) and go clockwise

Edit: re-reading this it sounds very rude, i didn't mean that way, sorry
I agree with you and I have tried the other way too, but I am still confused.
0
5 years ago
#8
(Original post by Marmite170899)
I agree with you and I have tried the other way too, but I am still confused.

from 0-10, how much sense does this make to you?

could you finish it from here do you think?

as someone above said, its all about sin and cos rules
0
#9
(Original post by DylanJ42)

from 0-10, how much sense does this make to you?

could you finish it from here do you think?

as someone above said, its all about sin and cos rules
I would give it an 8. Thank you I understand it much more now.
0
5 years ago
#10
(Original post by Marmite170899)
I would give it an 8. Thank you I understand it much more now.
8/10 is not too bad just practice lots of them and that will be 10/10 in no time its no problem
0
11 months ago
#11
Heya sorry I know this is an older post but I’m so confused on this same question. How do you know the angles from the bearings?
0
11 months ago
#12
(Original post by Emilyroseee59)
Heya sorry I know this is an older post but I’m so confused on this same question. How do you know the angles from the bearings?
Hiya! Rather than posting on an old thread is best to make a new one (in the maths forum)

If you have an angles 30* and 112* then the bearings are 030 and 112 respectively (from the north direction). So if you have a bearing 062, that’s 62* etc.

If you’re struggling to visualise it then post #8 should help?
0
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