Describe why pi is a real number but NOT a rational number

Pi is a real number because any number can be expressed in the form of (a+ib) where a is the real part and b is an imaginary part. its not a rational number because it cant be written as a fraction

Irrational numbers are numbers that can be written as decimals but not as fractions ... Pi is an irrational number because it cannot be expressed as a ratio (fraction) of two integers: it has no exact decimal equivalent, although 3.1415926 is good enough for many applications.