The Unit Circle
Drag the red point around the unit circle.
What is the radius of the circle?
Look carefully at the x & y co-ordinate of the red dot as you move it around the circle.
What do you notice about the numbers?
Compare the values of the x & y co-ordinate of the red dot with the values listed on the left hand side of the figure for Sine & Cosine.
What do you notice?
What are the coordinates of the red dot at ?