Question

Which of the following numbers is rational? A. 4/5 B.√27 C.4.020020002000002.... D.√31​

Answer 1

Hey buddy its easy
Answer is C part

Answer 2

Greetings from Brasil...

First let's define the rational number....

→ Division between two numbers with the detail that the dividend or denominator cannot be zero

A/B or A ÷ B

where B ≠ 0

(just for the sake of knowledge. If B = 0 we would have +∞ as an answer)

A ∈ ℤ

and

B ∈ ℤ*   (B ≠ 0)

In this way, when dividing A by B, we will obtain a whole number or a number with a decimal (finite decimal or periodic tenth)

Let's go to the alternatives

A = 4/5 = 0,8 (finite decimal)

4 ∈ ℤ and 5 ∈ ℤ*, so we have a rational number

B = √27 = 5.1961524227066318805823390245176

(There is no repetition of tithing periods (numbers after the point) - non-periodic tithe). So we have an Irrational Number

C = 4.020020002000002

There is no periodic tenth - Irrational Number

D = √31 = 5.5677643628300219221194712989185

Irrational Number - Non-periodic tithe