Length of (2, 3, 6)

Step by step

The question

Question: find the length of (2, 3, 6).

The length of v, written with double bars, is Pythagoras in more directions: square every entry, add, then take the square root.

1 Square and add

Every entry squared.

Careful!

The entries are squared first, then added.

Adding the entries themselves is not the length.

The squares: 4 + 9 + 36.

Added: 49.

2 Take the square root

49 is 7 squared.

So the length is 7.

3 Check

Let's check: the length squared must give back 49.

It does.

So the answer is right!

Let's look back.

First: square and add.

Then: take the square root.

Last: check.