Is 4.78 a rational number

Yes, 4.78 is a rational number because it can be expressed as a fraction where the numerator and denominator are integers and the denominator is not zero. In this case, 4.78 can be written as 478/100, which simplifies to 239/50. Since both 239 and 50 are integers and 50 is not zero, 4.78 is indeed a rational number.