When discussing the properties of numbers, one crucial distinction is between rational and irrational numbers. But what does it mean for a number to be irrational? In this article, we will analyze the number 90.790170 and determine whether it is rational or irrational, along with some insights and examples to enrich our understanding of these concepts.
What Are Rational and Irrational Numbers?
Rational Numbers
A rational number is defined as any number that can be expressed as the quotient or fraction of two integers, where the denominator is not zero. For example, numbers such as 1/2, 3, or 4 are all rational because they can be represented as fractions.
Irrational Numbers
On the other hand, an irrational number cannot be expressed as a simple fraction. This means that its decimal representation goes on forever without repeating. Common examples of irrational numbers include the square root of 2 (√2), π (pi), and e (Euler's number).
Analysis of the Number 90.790170
Now, let's evaluate the number in question: 90.790170.

Decimal Representation: The number 90.790170 is a finite decimal with a specific termination point. It ends after six decimal places, which means it does not continue infinitely and does not exhibit any repeating pattern.

Expressibility as a Fraction: Since 90.790170 is a finite decimal, it can be expressed as a fraction. For instance: [ 90.790170 = \frac{90790170}{1000000} ] Here, the numerator (90790170) and the denominator (1000000) are both integers, confirming that 90.790170 can be represented as a ratio of two integers.
Conclusion
Given the above analysis, we can conclude that 90.790170 is a rational number. It meets the criteria of being expressible as a fraction of two integers and has a terminating decimal representation.
Why Does It Matter?
Understanding the difference between rational and irrational numbers is fundamental in mathematics. Rational numbers are prevalent in everyday calculations, such as budgeting, measurements, and statistical data. In contrast, irrational numbers often surface in advanced topics like calculus, geometry, and physics.
Practical Example
Consider the practical application of understanding rational and irrational numbers in real life. If you are budgeting expenses, you're likely dealing with rational numbers: the cost of groceries, rent, or bills. Knowing the difference helps in accurately managing and representing these values, while also allowing for precise calculations in various fields, including finance and engineering.
Additional Value
If you’re curious about how to identify rational versus irrational numbers in your studies, here are some quick tips:
 Look for Terminology: Finite decimals and repeating decimals are rational. Nonrepeating, infinite decimals are irrational.
 Check for Perfect Squares: The square root of any nonperfect square number (like √3) is irrational.
 Familiarize with Constants: Numbers like π and e are wellknown examples of irrational numbers that often appear in mathematical formulas.
Conclusion
In summary, the number 90.790170 is rational because it can be expressed as a fraction and has a finite decimal representation. Understanding this classification aids in mathematical proficiency and is vital for effective realworld applications.
Attribution: This analysis expands upon concepts discussed in Q&A forums, including BrainlY responses where users seek clarity on rational and irrational numbers. For more engaging discussions, feel free to check platforms like BrainlY where students and educators converge to share knowledge.
By breaking down these concepts, we not only clarify our understanding of a specific number but also emphasize the broader implications of rational and irrational numbers in our mathematical journey.