The differences between rectangular and polar coordinates are explained as an introduction to polar. The big ideas are that x = rcos theta, y = rsin theta, r^2 = x^2 + y^2, and tan theta = y/x. Several examples are shown, with coordinates (r, theta). Then, some polar equations and graphs are shown and explained. Several equations and graphs are explained, as well as common polar graphs, limacons and cartioids. Roses are also shown for polar equations r = sin (k*theta). Horizontal and vertical tangents and slope of polar graphs are also discussed. This is a very full, important lesson.