How do you find the common ratio for 10,5,5/2,5/4,5/8,...?

10xx1/2=2; 5xx1/2=5/2; 5/2xx1/2=5/4; 5/4xx1/2=5/8; 5/8xx1/2=5/16............
The ${n}^{t h}$ term is $\frac{10}{2} ^ \left(n\right)$, $n = 0 , 1 , 2 , 3. \ldots .$
To find the ratio divide successive terms: 10/5=2;5xx2/5=2;5/2xx4/5=2.