ienarancillo
Given quadrilateral ABCD with AB = 47, BC = 31, CD = 61, angle B = 117 deg and angle C = 76 deg. FIND:
1. AD
2. angle A
3. angle D
4. AC
5. BD
NEED YOUR HELP PLEASE! GONNA PASS THIS TOMORROW! THANKYOU!
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ajprincess
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Have u got a diagram for this @ienarancillo?
ienarancillo
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no @ajprincess . :(
sorry. it's my homework and i really can't understand. PLEASE HELP
ienarancillo
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last one please. @ajprincess
In the figure, DB =16, angle BAD = 13 deg and angle ABD = 22 deg. Solve for CD.
THANKYOU!
ienarancillo
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@Callisto please help. :'(
Callisto
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Are you posting two questions here?
ienarancillo
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yes sir. :)
Callisto
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Not sir :S I'm not a guy.
Please do not post two questions in a single post!
For the first question, since the diagram is not given, we need to draw one ourselves.
|dw:1350743930628:dw|
Step 1: find BD, can you?
ienarancillo
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OMG! sorry! i didn't mean to! :'(
Callisto
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It's okay :)
Can you find BD?
Callisto
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By considering triangle BCD.
ienarancillo
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i'm going to try solving it now. :)
Callisto
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Tell me if you need some hints or so.
ienarancillo
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can i have a hint please. i am very confused in finding the angles which are along the transversal lines. :(
Callisto
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Use cosine law.
a^2 = b^2 + c^2 - 2bc cosA
ienarancillo
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awww. thanks.
Callisto
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Can you find BD now?
ienarancillo
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so.. i drew a separate triangle for this.
ienarancillo
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\[\sqrt{76^{2}+31^{2}-2(76)(31)\cos(76)}\] = 69.7
BD = 69.7
ienarancillo
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sorry it took so long. :"(
ienarancillo
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@Callisto Is this correct? please help.
Callisto
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Is CD = 6 or 76??
ienarancillo
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CD = 61 :)
Callisto
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You typed CD = 6 :S
Anyway. No, it's not correct though :|
ienarancillo
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OMG! so sorry again! :(
ienarancillo
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then what should i do next? :)
ienarancillo
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how should i find the angles? :)
Callisto
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You have to find BD first, and the BD you found is not right. Plug in 61 instead of 76
ienarancillo
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oh. sorry. is it 61.4? @Callisto
Callisto
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Yup. Next step: Find angle CBD
ienarancillo
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i used sine law for this. \[\frac{ \sin 76 }{ 61.4 } \frac{ \sin \angle CBD }{ 61 } = 74.6 degrees\]
ienarancillo
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@Callisto is this it? :)
Callisto
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Yup. So, now, find angle ABD.
ienarancillo
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11- 61.4 = 42.4 :)
ienarancillo
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i menat 117 - 61.4 = 42.4
ienarancillo
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*meant
ienarancillo
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@Callisto what should i do next? thanks so much for ur help.
Callisto
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Next?! Find AD :D
By considering triangle ABD.
ienarancillo
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sorry. honestly, i ought to do the same thing. :D
Callisto
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Hmmm you mean?
ienarancillo
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uhmm, i was solving it before you replied. i asked you just to be sure. :D
is this correct? :) @Callisto
Callisto
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Wait. It should be 117 - 74.6 = 42.4
And the answer you've got is wrong..
ienarancillo
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OMG. so sorry again, i just typed it wrong. but i guess, 42.4 is right? :)
Callisto
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Yes.
ienarancillo
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and is my AD correct? :)
Callisto
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I think so :|
ienarancillo
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sorry. i'll sum up all the remaining 3 answers. im sorry to bother you. but im in the process of understanding it now. :)
Callisto
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It's okay :) Glad that you're understanding it now :)
ienarancillo
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are my answers correct? :)
ienarancillo
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@Callisto :D
Callisto
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Wait... AD isn't 41.8
Callisto
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It's close to 41.8, but not 41.8
ienarancillo
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carelessness of mine. it's 41.4? :O
Callisto
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Yes!
ienarancillo
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but it's math error when i'm solving for angle a.
Callisto
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It should be
sin A/ BD = sin angleABD / AD
ienarancillo
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yes. i did that. \[\frac{ \sin \angle A }{ 61.4 }\frac{ \sin 42.4 }{ 41.4 } = MATH ERROR\]
Callisto
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Hmm.. can you round your answer above to 4 d.p.?
That way, you can get the answer!
ienarancillo
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uhmm, our instruction says 'all answers must be rounded off to the tenths place'. :'(