I'm not sure...
Because percentages can be expressed as fractions which are rational numbers
They need not be. You can have sqrt(23)% which would be irrational.
The answer will depend on whether you want percentage equivalents of rational numbers or one rational number as a percentage of another.
It is finding an equivalent number whose denominator is 100.
They are called rational numbers
It depends on the percentage. A 1 cm arc of a circle whose radius is 1 cm will represent 100*1/(2pi) % = 50/pi % and that is an irrational percentage. A semicircular arc of the same circle will represent 50%, which is rational.
No one invented percents.
20 percents
percents are numbers over 100
They are all the same, fractions can be turned into percents and percents can be turned into fractions. hope that helps :)
Percents are 100 times larger (and that is by definition!).