Answer:
a. √9
Step-by-step explanation:
a. √9 = 3
b.√15 = sqrt(5*3) cannot be simplified
c. √18 = sqrt(9) sqrt(2) = 3 sqrt(2) cannot be simplified farther
d. √20= sqrt(4) sqrt(5) = 2 sqrt(5) cannot be simplified farther
a is the only answer that is a rational number
