a)\ \frac18=\frac18 \times \frac {25}{25}=\frac{25}{200}=0,125\rightarrow \text{finita}\\\\ b)\ \frac73=\frac73 \times \frac33=\frac{21}9=\frac{18}9+\frac39=2+0,333...=2,333...\rightarrow \text{infinita e}\\\text{peri\'odica}\\\\ c)\ \sqrt3\text{ \'e um n\'umero irracional}\rightarrow \text{infinita e n\~ao per\'odica}\\\\ d)\ \frac85=\frac85 \times \frac22=\frac{16}{10}=1,6\rightarrow \text{finita}\\\\