A number is called irrational if it cannot be written in the form
p
/
q
where p and q are integers and q ≠ 0.
√
36 can be simplified as √
36 = ±6.
Both 6 and − 6 are rational numbers.
So, √
36 is a rational number.
6 is not a perfect square so, √
6 cannot be simplified further.
All irreducible square roots are irrational.
So, √
6 is an irartional number.
0.36 can be written as
36
/
100
using decimal place value.
So, it is a rational number.
− 12
/
4
is already in the form of
p
/
q
and both − 12 and 4 are integers.
So, it is a rational number.
Therefore, option (b) is correct.