Based on the
Pythagorean theorem I think you can calculate the distance between two points defined by x,y coordinates taking under consideration that they form a right-angled triangle with their x and y's being the legs and the distance being the hypotenuse.
Without digging too deep into it and checking if it is indeed true for all posible combos of x,y (location of points in each of the four cartesian, ermmm, is quadrants the correct english word?, not sure)....aaanyway.....I
THINK (please do bother to check, Im not sure)
If we have point A (xA,yA) and point B(xB,yB) and their distance d then
d squared = (xB-xA) squared + (yB - yA) squared
therefore the distance d is
d= square root of ( (xB-xA)squared + yB-yA)squared)
For the angle, I dont have a clue! lol
EDIT: distance calculation confirmed, a few lines down in the wiki article above, just saw it! lol