Power of a PointOne unit that we do in Geometry deals with lengths of segments in, or partially in, a circle. This site lets the user drag the point of intersection of the segments to see these relationships in action and holding true.

Dirt Bike Dilemma This is a lesson on linear programming. The basic problem is a bike shop has a certain number of different kinds of parts. The goal is to figure out which bikes and how many of each to make in order to maximize profit with these parts. It is a very neat lesson because it involves hands on material, graphing calculator usage and extensions, and group work. This is exactly what I'm looking for to help the kids see more meaning behind lines and points of intersection.

Exploring Linear Data Given sets of data, students discover the relationship between the number of oil changes each year and the cost of engine repairs as well as the relationship between the weight of a bike and the height of it's jump. Students explore the meaning of slope and also use a linear regression tool on the computer to help them come up with the lines of best fit.

These three sites were all found on the NCTM site called illuminations. Oh my goodness, there are so many more good ones on this site alone.

Math TV Watch short tutorials as different math teachers do example problems on the board.