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Is 3/4 rational or irrational

Step by step, with the reason for every step · Rational or irrational · Foundations

Step by step

The question

Question: is 3/4 rational or irrational?

34

Rational means: it can be written as a fraction, with whole numbers on top and at the bottom.

Then its decimal stops, or repeats for ever.

Irrational means: no fraction works.

Its decimal never stops and never repeats.

rational = a fraction of whole numbers
decimal stops or repeats

1 Look at the fraction

It is already a fraction.

The top, 3, and the bottom, 4, are whole numbers.

top 3, bottom 4: whole numbers

Careful!

The decimal may go on for ever.

That is fine, if it repeats.

Rational only asks for a fraction.

Careful: its decimal may go on, but it repeats

So 3/4 is rational.

A fraction of whole numbers is rational.

= 34 is rational

2 Check

Let's check with the decimal: 3 divided by 4 is 0.75.

It stops.

So the answer is right!

3 ÷ 4 = 0.75

Let's look back.

First: look at the fraction.

Last: check.

Answer
= 34 is rational

Your turn

Try this one yourself, then check:

48
Show the answer
rational

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