Question

For $\Delta ABC$. Choose incorrect option

• A. $\tan \theta =\frac{3}{4}$
• B. $\sin \theta =\frac{4}{5}$
• C. $\cos (90-\theta )=\frac{3}{5}$
• D. $\cos \theta =\frac{4}{5}$

Answer 1

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


We know
$\sin \theta =\frac{P}{H}=\frac{AB}{AC}$

Length of $AC=\sqrt{(AB{)}^2+(BC{)}^2}=\sqrt{(3{)}^2+(4{)}^2}=5m$
$\therefore \sin \theta =\frac{AB}{AC}=\frac{3}{5}$