two distinct points (for example, a game object position and the mouse cursor position) in an area can always be two corners of a Right Triangle (Triângulo-retângulo in ptbr). A triangle has three sides: The Hypotenuse, the Adjacent and the Opposite.
The distance between two points in the X axis corresponds to the Adjacent side of a triangle, The distance between two points in the Y axis corresponds to the Opposite side of a triangle.
The Hypotenuse is the shortest distance between the two points.
This means we can use trigonometry to handle many interactions between objects when programming visual stuff.