Question

If $\sin \theta =\frac{3}{5}$, find the values of $\cos \theta$

• A. $\frac{3}{4}$
• B. $\frac{4}{5}$
• C. $\frac{5}{7}$
• D. $\frac{4}{2}$
• E. non of these

Answer 1

The correct option is B $\frac{4}{5}$

$\because \sin \theta =\frac{3}{5}=\frac{p}{h}$
$\therefore b^2=h^2-p^2[\because h^2=p^2+b^2]$
$={\left(5\right)}^2-{\left(3\right)}^2=25-9$
$b^2=16$
$\therefore b=\sqrt{16}=4$
$\cos \theta =\frac{b}{h}=\frac{4}{5}$