Question

ERGENTWhich expression represents a rational number?

Answer 1

`(2)/(7)+√(121)`

Explanation:

Rational Numbers

Rational numbers are those that can be expressed as the fraction

`(a)/(b)`

where a and b are integers and b≠0.

Examples of rational numbers are:

4/3, -100/34, 9, -5, 0

Note the last three numbers are integers but they also can be called rationals because they can be written as 9/1, -5/1, 0/1.

Irrationals are those numbers that cannot be expressed as fractions, i.e. they are not rationals.

Examples of irrational numbers are:

`2\pi,\ √(5), \sin 4^\circ`

Analyzing the available options:

`√(18)` is not a rational number because the value of the root is not exact

π and
`√(11)` are not rational numbers either, but
`√(121)=11`.

Thus the only rational number from the list is

`\mathbf{(2)/(7)+√(121)}`