Which one of the following is a rational number?

Question: Which one of the following is a rational number?

Solution:
We know,
rational + irrational = irrational

√2 × √9
= √2 × 3
= 3√2 [irrational]

√3 × √4
= √3 × 2
= 2√3 [irrational]

√2 × √16
= √2 × 4
= 4√2

√3 × √27
= √3 × 3√3
= (√3)² × 3
= 3 × 3 = 9 [rational number]