This Instructional Activity is a part of the Lesson 15, Unit 4, Grade 8. Now let's look more closely at finding the number that will be the slope of a line. Suppose a non-vertical line is given in the coordinate plane. We let be P the point on line that goes through the origin. Next, we locate a point Q, exactly one unit to the right of point P. Next, we draw a line through point Q that is parallel to the y-axis.