Under Lynn's persistent urging, Johnny nodded, hurriedly took out the notebook cradled in his arms, flipped to the latest page, and pointed to the problem on it before asking, "Professor, I still don't quite understand the Cartesian coordinate system you mentioned today… especially this question…"
"To determine the distance between two points, you need to use the Pythagorean theorem we talked about before. You can mark the difference in the x and y coordinates on the axis, then connect them with a line, and now you have two right triangles joined together. This brings us back to a problem of geometry…" Lynn explained the problem-solving approach to Johnny in a simple and clear manner.
By serious business, naturally, he meant giving private lessons!
