If Sin A = 3/5 then Cos A =A) 3/4B) 4/5B) 5/4D) 4/3

1.	If Sin A = 3/5 then Cos A =A) 3/4B) 4/5B) 5/4D) 4/3
Answer» Correct option is: B) \(\frac{4}{5}\) We have sin A = \(\frac 35\) Now \(cos^2\, A = 1 -sin^2A = 1 -(\frac 35)^2 = 1 - \frac 9{25} \) \(= \frac {25-9}{25} = \frac {16}{25} = (\frac 45)^2\) \(\therefore\) cos A = \(\frac{4}{5}\) Correct option is: B) \(\frac{4}{5}\)

Answer»

Correct option is: B) \(\frac{4}{5}\)

We have sin A = \(\frac 35\)

Now \(cos^2\, A = 1 -sin^2A = 1 -(\frac 35)^2 = 1 - \frac 9{25} \)

\(= \frac {25-9}{25} = \frac {16}{25} = (\frac 45)^2\)

\(\therefore\) cos A = \(\frac{4}{5}\)

Correct option is: B) \(\frac{4}{5}\)

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