CircleTrig Geoboard

Explore Geometry and Trigonometry The CircleTrig Geoboard, designed by Henri Picciotto, offers a new way to reveal basic right-triangle and unit-circle trigonometry concepts. One side is designed for exploring trigonometry with pegs every 15 degrees around the circle and every 2 centimeters around the perimeter of the circumscribing square, and provides scales for measuring angles and trigonometry values. The 11-peg by 11-peg square on the other side can be used to make important connections between geometry and algebr