- John Golden
I saw this interesting tool at the hardware store the other day. It's a cleverly designed thing, where a slider on the main arm opens an angle measure at the tip. You can lock it in place to copy the angle at another place or on a block of wood, or you can measure the angle by looking at a scale on the center arm. That was interesting, too. How do you go from a distance on the arm to an angle measure of the rhombus that's formed?
More GeoGebra at mathhombre.blogspot.com