Testing if a point is inside a triangle (3 methods)

How do computers test whether a point is inside a triangle or not? (one form of collision detection).[br][br]Which of the three methods is fastest? See here for the answer: [url=http://blackpawn.com/texts/pointinpoly/]www.blackpawn.com/texts/pointinpoly/[/url]

Information: Testing if a point is inside a triangle (3 methods)