Unit Circle (radius is 1 unit long)

3 2 2 2 !

1 2 1

!

2

" 2

2

!

2

2

! 2

2

!

1 !2

"1

! " 3

"1

!

2

!

3 2

!

" 2 2!

" 3 2

! !

Red Lines represent: √3 2 Blue Lines represent: √2 2 Green Lines represent: 1 2

cosine

Unit Circle (Back of left hand)

1.) Fold down the finger of the angle you are looking for. 2.) To find the cosine, you count how many fingers you have to the left of the finger that is folded down. Place this number under the square root sign. 3.) Put this new number over 2 (which is the back of your hand).

45°

30°

60° 0°

90°

2

Think of each finger as being a “tick mark”

1.) Fold down the finger of the angle you are looking for. 2.) To find the sine, you count how many fingers you have to the right of the finger that is folded down. Place this number under the square root sign. 3.) Put this new number over 2 (which is the back of your hand).

sine

ED WILLIAMS’ METHOD FOR RECALLING CIRCLE

THE

UNIT