Question

Why the order of the coordinates does not matter when calculating length

Answer 1

The formula for calculating length is:

`\sqrt{ (x_b-x_a)^(2) + (y_b-y_a)^(2) }`

We can also write
`x_a - x_b` or
`y_a - y_b`
Why it does not matter?
Let's assume we have 2 numbers, a and b.
When we perform a subtraction:

`a-b`, we get another number
`c`
When we perform another subtraction:

`b-a`, we get a number
`-c`

When we raise
`c` or
`-c` to the power of 2, the result is the same,
`c^(2)`.