What is the reciprocal of 4/9?

1. To find a reciprocal, invert the fraction. 2. Swap the numerator 4 and the denominator 9. 3. This gives 9/4. 4. Multiplying 4/9 by 9/4 gives 36/36, which simplifies to 1, confirming the reciprocal is correct. _Source: OpenStax Prealgebra (CC BY 4.0), Ch 4 "Fractions", section 4.2 Multiply and Divide Fractions_