Learning goals: Teacher Facing Calculate the distance between two points in the coordinate plane by using the Pythagorean Theorem and explain (orally) the solution method. Generalize (orally) a method for calculating the length of a line segment in the coordinate plane using the Pythagorean Theorem. Full lesson plan (warm-up, activities, synthesis, cool-down prompt) from 8.8 Pythagorean Theorem and Irrational Numbers, Grade 8.