Critique the following proof Definition 44 Between Let A B C

Critique the following proof...

*Definition 4.4  (Between). Let A, B, C be collinear points with coordinates a, b, c respectively. Then B is between A and C (denoted A?B ?C) provided that either a < b < c or c < b < a.

Solution

Here we are assuming the required conclusion and as a consequence we get a fact which is not false.

But this is not a proof, to prove we can assume the hypothesis only as true,then by argument we have to show conclusion is true.

Or even we can usecontrapositive method.n