Question

How do you find the missing coordinate if the 1st coordinate is (13,5) and the midpoint is (7, -4)?

Answer 1

Missing coordinate is `(1,-13)`

Explanation:

Let the second coordinate be `(x,y)`. Now the midpoint of `(x,y)` and `(13,5)` is

`((x+13)/2,(y+5)/2)`. But as midpoint is given as `(7,-4)`

`(x+13)/2=7` and `(y+5)/2=-4`

or `x+13=7*2=14` and `y+5=-4*2=-8`

or `x=14-13=1` and `y=-8-5=-13`

Hence, missing coordinate is `(1,-13)`