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1 vote
AB Complementary

SinA = 4/5 find Cos b​

User Ardi
by
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1 Answer

4 votes

Answer:


cos\:b = (4)/(5)

Explanation:

It is given that: a and b are complementary.


\therefore a + b = 90\degree\\\\\therefore a = 90\degree - b\\\\Assuming\: sin \: ratio \: on\: both\: sides\\\\sin\:a = sin(90\degree - b)\\\\\therefore (4)/(5) = sin(90\degree - b)...(\because sin\:a = (4)/(5))\\\therefore (4)/(5) =cos\:b...\{\because sin(90\degree - \theta) = cos\: \theta\} \\\\\huge\purple{\boxed{\therefore cos\:b = (4)/(5)}}\\

User Dan Coates
by
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