However, rather than proving pi is irrational directly, it's also possible to confirm irrationality using a different property of the number.

Rational numbers can be fractions of integers. Irrational numbers cannot be expressed as ratios. Decimal representations help identify them. Pi and Euler's number are irrational.

Because every transcendental number is irrational, any proof showing that pi is transcendental also proves that pi is irrational.