Answer:
<h2>Irrational.</h2>
Step-by-step explanation:
This number is irrational.
Decimal numbers can be finite or infinite. Specifically, irrational numbers are only infinite, but rational numbers can be both, infinite or finite. So, how to distinguish them?
Actually, we can see the difference looking for patterns or repetitions. When the decimal number is infinte but has a pattern like the number 1.6666666..., then that's a rational number, because its "rationality" is the pattern.
On the other hand, if the decimal number is infinite and it doesn't have a repetitive pattern, like the given -0.8662866239, then that's a irrational number, because it doesn't have a repetition which makes it "rational".
Therefore, the given number is irrational.