Yes, 4/9 is a rational number. A rational number is defined as any number that can be expressed as the quotient or fraction of two integers, where the denominator is not zero.
In this case, 4 is the numerator and 9 is the denominator. Both 4 and 9 are integers, and since 9 is not zero, 4/9 meets the criteria for being a rational number.
Furthermore, rational numbers can be represented in decimal format. When you divide 4 by 9, you get approximately 0.444…, which is a repeating decimal. This further confirms that 4/9 is a rational number because rational numbers can also exist in decimal form, whether terminating or repeating.