Answer
Amplitude=$\dfrac{4}{3}$
Period= $3\pi$
Work Step by Step
Recall:
For $y=A\sin{(ωx)}$, we have:
$\text{Amplitude}=|A|\quad \quad \text{and} \quad \quad \text{Period}=T=\frac{2\pi}{ω}$
In $y=\frac{4}{3}\sin (\frac{2}{3}x)$we have $A=\frac{4}{3}$ and $\omega=\frac{2}{3}$, so
Amplitude= $|A|=|\frac{4}{3}|=\frac{4}{3}$
Period $T=\frac{2\pi}{\omega}=\dfrac{2\pi}{\frac{2}{3}}=3\pi$
