Answer
$\cos \theta = \frac{4}{5}$ and $\tan \theta= \frac{3}{4}$
Work Step by Step
$\cos^{2}\theta+\sin^{2}\theta=1$
$\implies \cos^{2}\theta= 1-\sin^{2}\theta=1-\frac{9}{25}=\frac{16}{25}$
$\implies \cos \theta= \frac{4}{5}$ ($\cos \theta$ is positive as $0\leq\theta\lt\frac{\pi}{2}$)
$\tan \theta=\frac{\sin\theta}{\cos\theta}=\frac{\frac{3}{5}}{\frac{4}{5}}=\frac{3}{4}$.
