Write 3.14159 correct to 3 significant figures.

Step by step

The question

Question: round 3.14159 to 3 significant figures.

1 Find the first significant figure

In 3.14159, the first significant figure is 3.

The first significant figure is the first digit that is not 0.

2 Count the figures

We count 3 figures from there: 3, 1, 4.

The 3rd figure, 4, is in the hundredths place.

So we round to the nearest hundredth.

3 Look at the next digit

Now we look at the next digit to the right.

It is 1.

5 or more: we round up, the hundredths digit goes up by 1.

4 or less: we round down, it stays.

1 is 4 or less, so we round down.

4 Keep the size

We stop after the 3rd figure.

So 3.14159 is about 3.14.

So 3.14159 to 3 significant figures is 3.14.

5 Check

Let's check.

3.14 has 3 significant figures: 3, 1, 4.

And it is close to 3.14159.

So the answer is right!

Let's look back.

First: find the first significant figure.

Then: count the figures.

Then: look at the next digit.

Then: keep the size.

Last: check.