Hundred as a denominator as 209 over 25 is obtained by mulyiplying numerator and denominator by 4

Solution:
Given that we have to get hundred as a denominator as 209 over 25
Thus the given fraction is:

Now we have to get 100 as denominator
If you multiply both the numerator and denominator of a fraction by the same non-zero number, the fraction remains unchanged in value.
Therefore, equivalent fractions can be created by multiplying or dividing the numerator and denominator by the same number
Muliply and divide by 4, so that 25 muliplied by 4 gives 100

Thus the denominator is 100