Final answer:
The number 15 is a rational number because it can be expressed as the fraction 15/1, with both numerator and denominator being integers, and the denominator not being zero. It is also a whole number, integer, and natural number.
Step-by-step explanation:
The number 15 is indeed a rational number. A rational number is defined as a number that can be expressed as a fraction or ratio of two integers, where the numerator and denominator are both integers, and the denominator is not zero. In this case, 15 can be expressed as the fraction 15/1 where 15 is the numerator and 1 is the denominator. Both numbers are integers, and the denominator is not zero, satisfying the definition of a rational number.
Moreover, 15 is a whole number, integer, and also a natural number since it is a positive number without any fractional or decimal part. It is not a perfect square root since the square root of 15 is an irrational number, and it is not a terminating decimal or repeating decimal since it has no decimal component.