Final answer:
-2.16 is a rational number because it can be expressed as a fraction of two integers, specifically -54/25.
Step-by-step explanation:
The question is whether -2.16 is a rational number. A rational number is defined as a number that can be expressed as the quotient or fraction of two integers, with the denominator not being zero.
In this case, -2.16 can be written as -216/100, which simplifies to -108/50 or further to -54/25. Since it can be expressed as a fraction of two integers, -2.16 is indeed a rational number.