Which sequence is modeled by the graph below

.05/5=.5/5=1/10  so the common ratio is 1/10 and the first term is 5.

Any geometric sequence can be expressed as:

a(n)=ar^(n-1), a=initial term, r=common ratio, n=term number so this sequence is:

a(n)=5(1/10)^(n-1)   (the bottom answer)