The unit circle is a circle with radius

The unit circle is a circle with radius 1 and center at the origin represented by the equation x 2+y 2=1.

Important points of the unit circle occur at eighths. To label, begin at 0 - the far right of the circle. The circumference of a circle is 2 and we are dividing the circle into eighths, which means the top half is divided by four. We can then count from pi over 4 to pi and continue around. Then, simplify.

Important points of the unit circle also occur at twelfths. To label, begin at 0 - the far right of the circle. The circumference of a circle is 2 and we are dividing the circle into twelfths, which means the top half is divided by sixths. We can then count from pi over 6 to pi and continue around. Then, simplify.

° 45 60 ° 15 ° 30 0° 0° 180° 360° 33 0° 24 270° 22 0° 0° 5° ° 0 1 2 30 Dividing 360° by twelve yields 30°, the inner circle an thus be labeled. 5° 0° The sum of the central angles in a circle is 360°. Dividing this by eight yields 45°, the outer circle angles can thus be labeled. 13 12 We can then overlap the divisions of the unit circle by eighths, the outer circle, and the divisions of the unit circle by twelfths, the inner circle, and add angles. 90° The unit circle is a circle with radius 1 and center at the origin represented by the equation x 2+y 2=1. 31 5°

° ° 45 5° 60 13 0° 12 Quadrant II 15 0° (-x, y) ° 30 0° 180° 33 ° 0 1 2 Quadrant IV 0° 31 (x, -y) 5° 5° Quadrant III (-x, -y) 270° 24 0° 30 0° 22 (x, y) represents (cos, sin) of any given angle or radian. Only the values for one fourth of the circle need to be memorized; they remain the same for the other three fourths of the circle, changing only the signs according to the quadrants. 90° The unit circle is a circle with radius 1 and center at the origin represented by the equation x 2+y 2=1.

90° 60 ° 0° 12 13 45 ° ! ° S ° N 30 O e I h T t A d L e U at 0° 180° T A e. r R e c l G c e ir N v c a O 33 ° C 210 u h nit 0° 31 u o 5° Y 5° 270° 24 0° 30 0° 22 5° 15 0