Can someone explain the 'ambiguous' sine rule please

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can someone please explain the ambigious rule to me please wether its with the aid of a diagram

i get that its used to find that extra thing

but how would you know when to use it

in the book it says' when the angle you are finding is larger than the given angle there are two possible answer' someone please explain THANK YOU

Posted Sat 17th March, 2012 @ 18:00 by Xenxen

2 Answers

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The sin rule is a/sinA=b/sinB=c/sinC

A little a,b,c is used to indicate the length of a given side and an capital A,B,C is used to represnt an angle

it can be used in any tringle that has either one angle and two sides given OR two angles and one side

For example if you had a triangle where a=8cm, Angle A=35 degrees and Angle B =70 degrees and you need to find what length b was you could use the sine rule

a/sinA=b/sinB

8/sin35=b/sin70

Rearrange it to get B by itself(times by Sin70)

b= 8sin70/sin35 which would be 13cm

Answered Sat 17th March, 2012 @ 20:38 by curlytop96
Edited by curlytop96 on Sat 17th March, 2012 @ 20:42
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yh but thats not ambigious anywy i got the answer now

Answered Sat 17th March, 2012 @ 22:04 by Xenxen