Start with first-quadrant values
For 30°, 45° and 60°, the coordinate magnitudes come from 1/2, √2/2 and √3/2. The order swaps between sine and cosine.
Match standard angles and radians with their exact (cos θ, sin θ) coordinates. Ten questions, instant feedback, and a visual point on the circle every round.
Remember: a unit-circle point is (cos θ, sin θ). Signs come from the quadrant.
Every point on the unit circle has radius 1. At angle θ, the horizontal coordinate is cos θ and the vertical coordinate is sin θ, so the point is (cos θ, sin θ).
For 30°, 45° and 60°, the coordinate magnitudes come from 1/2, √2/2 and √3/2. The order swaps between sine and cosine.
Quadrant I is (+,+), II is (−,+), III is (−,−), and IV is (+,−). The reference-angle magnitudes stay the same.
30° is π/6, 45° is π/4, 60° is π/3 and 90° is π/2. Practice both notations until the conversion feels automatic.
These five anchors generate the standard unit-circle coordinates. The practice game above expands them through all four quadrants.
| Degrees | Radians | cos θ | sin θ | Point |
|---|---|---|---|---|
| 0° | 0 | 1 | 0 | (1, 0) |
| 30° | π/6 | √3/2 | 1/2 | (√3/2, 1/2) |
| 45° | π/4 | √2/2 | √2/2 | (√2/2, √2/2) |
| 60° | π/3 | 1/2 | √3/2 | (1/2, √3/2) |
| 90° | π/2 | 0 | 1 | (0, 1) |
From 0° to 90°, cosine decreases as 1, √3/2, √2/2, 1/2, 0. Sine uses the same list in reverse.
At 150°, the reference angle is 30°. The magnitudes are √3/2 and 1/2, then Quadrant II makes x negative and y positive: (−√3/2, 1/2).
Memorize the first-quadrant exact values for 0°, 30°, 45°, 60° and 90°, their radian equivalents, and the sign pattern by quadrant. Symmetry generates the rest.
On a circle of radius 1, cosine is the horizontal projection of the radius and sine is the vertical projection. Therefore the point reached by angle θ has coordinates (cos θ, sin θ).
Practice one direction at a time: first angle to coordinate, then coordinate to angle, then use mixed mode. Short repeated recall is more reliable than repeatedly rereading a completed chart.