Which number is an irrational number?

a) �ã3 b) -13.5 c) 7/11
d) 1/ �ã9

What is the definition of an irrational number?

Since this is not my area of expertise, I searched Google under the key words "irrational number" to get these possible sources:

http://mathworld.wolfram.com/IrrationalNumber.html
http://en.wikipedia.org/wiki/Irrational_number
http://www.mathsisfun.com/irrational-numbers.html
http://mathforum.org/dr.math/faq/faq.integers.html
http://www.themathpage.com/aPreCalc/rational-irrational-numbers.htm

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.

I hope this helps. Thanks for asking.

Oh, irrational numbers, don't they drive us all a little crazy? Well, let's see if we can find the culprit here.

a) √3 - Well, that sneaky square root of 3 certainly seems irrational. It's like the child who always argues with you for no reason.

b) -13.5 - Sorry buddy, you're not irrational, you're just a negative decimal.

c) 7/11 - Nope, 7/11 is a rational fraction. But hey, if you're looking for a convenience store, I can point you in the right direction!

d) 1/√9 - Ah, we've got another square root. And since the square root of 9 is 3, then 1/√9 simplifies to 1/3, which is rational.

So, the answer is a) √3. It's a prime example of an irrational number. Just like that friend who always tells terrible jokes, but you can't help but laugh anyway.

An irrational number is a number that cannot be expressed as a ratio of two integers. In other words, it cannot be written as a fraction.

Using this definition, the number "a) �ã3" is an irrational number.

An irrational number is a number that cannot be expressed as a simple fraction or ratio of two integers. It is a number that is not a rational number.

In the given options:
a) √3 (square root of 3) is an irrational number. To determine this, we can use the definition of an irrational number that it cannot be expressed as a simple fraction. Since the square root of 3 cannot be expressed as a fraction, it is irrational.

b) -13.5 is a rational number. A rational number is any number that can be expressed as a simple fraction or ratio of two integers. -13.5 can be written as -27/2, which is a fraction, making it a rational number.

c) 7/11 is a rational number. It can be expressed as a fraction of two integers, making it rational.

d) 1/√9 (1 divided by the square root of 9) is a rational number. The square root of 9 is 3, so 1/3 is a fraction and can be expressed as a ratio of two integers, making it rational.

Therefore, the only option that represents an irrational number is a) √3.