The distance formula is derived from which result?

1. Two points on the plane can be joined by a right triangle whose legs run across and up. 2. The horizontal leg is the difference in x and the vertical leg is the difference in y. 3. The Pythagorean Theorem then gives the straight line joining them as the hypotenuse. 4. Taking the square root of the sum of the two squared differences gives the distance formula. _Source: OpenStax College Algebra (CC BY 4.0), section 2.1 The Rectangular Coordinate Systems and Graphs_