The Trigonometer

"When my students entered the room and saw the trigonometers on their tables, they gathered in amazement. They engaged immediately.  I love how the trigonometer helps my students view trigonometry numerically, which frees them from having to draw right triangles every time they try to evaluate a trig function.  It enables them to see numeric approximations to expressions like cos(170 degrees) that previously would have produced blank stares."