OK, so I actually need help here. so my teachers all suck, and they're doing a terrible job at teaching me. So we're learning about using the Pythagorean theorem to find the distance on a coordinate plane. they gave this as an example: To determine the distance between points A and B, consider the horizontal distance and the vertical distance you would travel to go from point A to point B. The horizontal and vertical distances form a 90° angle and they are considered legs of a right triangle, where the shortest distance between points A and B is the hypotenuse.

and then the end equation was

so how does this work? like can someone give me a step by step explanation on how to do this? Please, I'm begging you.