A fraction is terminated if denominator consist of one of or both primes number: 2 and 5.
1) s=225=5*5*9. for r=1 r/s^2 is not terminated, for r=9^2 the fraction is terminated
2) r=81. for s=17 r/s^2 is not terminated, for s=2*9^2 the fraction is terminated
1)&2) 9^2/(5*5*9)^2=1/5^4 is a terminated fraction. sufficient.
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