Irrational Numbers

This is the circumference of a circle divided by its diameter. This number is the same for every circle. The number pi (written as π) is approximately 3.14159265358979323…. The ellipsis (…) shows that the number continues onward to infinity.

Most irrational numbers are found in square roots.

To square a number means to multiply the number by itself. For example, 5 x 5 is squaring the number “5”. This can also be stated as five squared which will then look like this “5²” with the little exponent “2”. (5 x 5 = 25)

As the answer here is the number “25”, it is stated as the “square root of 25” is “5” because “5” multiplied by itself gave us “25”.

Square roots are either “perfect” meaning the whole number has a squared number that, when multiplied by itself will equal the number, i.e., 9 is a perfect number because 3 x 3 = 9, or they are “imperfect” which means there is no number when multiplied by itself will equal the square root. For example, the number 15 has no number that when multiplied by itself will give you the number 15. Therefore, 15 is an “imperfect root” and it will provide us with an “irrational” number.

The math symbol that represents a square root is: “√”. So using the example above it would read:

√25 = 5

Because there is no actual solution to finding a square root, the use of calculators is generally needed. In fact, for this quiz a calculator will be a must to find the irrational number. Although an irrational number can go to an infinite distance to the right of a decimal, for this quiz we will only go as far as four digits to the right.