If you have two points on a graph and are asked to find the distance between these two points, then this can easily be done using Pythagoras theorem. Suppose you are asked to work out the distance between 2 points A and B.
STEP 1 – Using coordinates of points A and C, find distance ‘a’
STEP 2 – Using coordinates of points B and C, find distance ‘b’
STEP 3 – Using Pythagoras theorem, find distance ‘c’