Find the possible values of angle ##∠ADB##

AI Thread Summary
The discussion focuses on finding the possible values of angle ∠ADB, with calculations showing that BC equals 10.25 cm using the cosine rule. For part (b), BK is determined to be 3 cm through the sine rule, leading to ∠BDK being 48.59 degrees and consequently ∠ADB being 131.4 degrees. An alternative value of ∠ADB is noted as 48.59 degrees when BD is positioned on the opposite side of the perpendicular line. Participants suggest that providing step-by-step calculations rather than just outcomes would enhance clarity. The conversation emphasizes the importance of precise geometric representation, particularly in non-scaled diagrams.
chwala
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Homework Statement
See attached ( kindly allow me to post as it is on exam script)
Relevant Equations
Understanding of the Triangle
1686582692210.png


My take:

1686582845878.png


I got ##BC=10.25## cm, using cosine rule...no issue there. For part (b)
##BK=3cm## using sine rule i.e ##\sin 30^0 =\dfrac{BK}{6}##
Thus it follows that ##∠BDK=48.59^0## ...⇒##∠ADB=131.4^0## correct...any other approach?

Also:

##∠ADB=48.59^0## when BD is on the other side of the given perpendiculor line.

cheers guys
 

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Seem ok to me.
'Not to scale' is an understatement....

And instead of outcomes, post steps: ##\angle ADB = \arcsin 3/4 = ...## is so much clearer !

##\LaTeX ## degrees is ^\circ : ##30^\circ##

##\ ##
 
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Likes chwala and SammyS
BvU said:
Seem ok to me.
'Not to scale' is an understatement....

And instead of outcomes, post steps: ##\angle ADB = \arcsin 3/4 = ...## is so much clearer !

##\LaTeX ## degrees is ^\circ : ##30^\circ##

##\ ##
@chwala ,

In case you miss @BvU 's post, it bears repeating... on all counts. :wink:
 
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