Answer:
The correct option is are 2, 3 and 4.
Step-by-step explanation:
Rational number: If a number can be defined in the form of p/q where, p and q are integers and q≠0, then it is known as rational numbers. For example: 0.2, 1/3 and 1 etc.
Irrational number: If a number can not be defined in the form of p/q where, p and q are integers and q≠0, then it is known as irrational numbers. For example: 0.222..., √2 and π etc.
[tex]\pi\sqrt{36}=6\pi[/tex]
It is an irrational number because π is an irrational number.
[tex]7\sqrt{5}-\sqrt{245}=7\sqrt{5}-7\sqrt{5}=0[/tex]
It is a rational number.
[tex]\frac{4}{5}+\frac{3}{8}=\frac{32+15}{40}=\frac{47}{40}[/tex]
It is a rational number.
[tex](4\sqrt{7})(2\sqrt{7})=(4\times 2)(\sqrt{7\times 7})=8(7)=56[/tex]
It is a rational number.
[tex]\sqrt{100}+\sqrt{5}=10+\sqrt{5}[/tex]
It is an irrational number because sum of a rational and an irrational number is always an irrational number.
Therefore the correct option is are 2, 3 and 4.
