In the context of enrollment increasing by 5% each year, the common ratio can be determined from the percentage increase.
A 5% increase means that the new enrollment each year is 105% of the previous year's enrollment. This can be expressed as:
\[ \text{New Enrollment} = \text{Old Enrollment} \times 1.05 \]
In this equation, the factor 1.05 is the common ratio, as it shows how much the enrollment increases each year relative to the previous year.
Thus, the common ratio in this situation is 1.05.