an irrational number/value is one you cannot express in terms of a ration, or a fraction, it cannot be written as fraction
now 291.87... is simple, two decimals, so you use two zeros at the botom and end up with [tex]\bf \cfrac{29187}{100}[/tex] and boom, there you are, a fraction, nice and dandy
now, let's see the first one -√(127) well, low and behold, 127 is a prime number, and and thus is has no two factors that'd serve as root, so, there's no rational root that'd give that, that makes it irrational
