Question

if sin theta =4/5 then find cos theta

Answer 1

Sin A= 4/5=prependicular/hypotenuse
CosA =Base/hypotenuse
Base=√hyp.^-prep.^
=√9 =3
Base=3/5

THANKS!

Answer 2

Answer:

$\cos\theta = \frac{3}{5}$

Step-by-step explanation:

$Given sin\theta = \frac{4}{5}$

/* we know the Trigonometric identity:

$\boxed {cos^{2}\theta=1-sin^{2}\theta }$

Now,

$cos^{2}\theta = 1-\big(\frac{4}{5}\big)^{2}\\=1-\frac{16}{25}\\=\frac{25-16}{25}\\=\frac{9}{25}$

$\implies cos\theta =\sqrt{\frac{9}{25}}\\=\frac{3}{5}$

Therefore,

$\cos\theta = \frac{3}{5}$

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