Question

find one irrational number between 5 and 6

Answer 1

Irrational numbers are such numbers which cannot be written in the form of p/q, for any integers p, q and
 q is not equal to 0 is called an irrational number

Decimal form of irrational numbers are non terminating and non recurring.
Decimal form of irrational numbers are indefinite.

Irrational number between 5 and 6 : 
(5+6)÷2=11÷2 ( a+ b ÷ 2)
Decimal form of irrational number:
 5.46783241................
5.4326589752............

Answer 2

you can write anything by putting a decimal it will be considered as irrational only but it should not end nor should repeat like....
5.0879456213486..................
hope it helps!