One full circle is 360∘, which converts to 2𝜋 radians using the relationship 180∘=𝜋 radians.
At 90 ∘, the terminal side of the angle intersects the unit circle at the topmost point, which has coordinates (0,1).
The sine of 30∘ is 0.5, as derived from the 30°-60°-90° triangle. In such a triangle, the side opposite the 30° angle is always half the length of the hypotenuse.
For 45∘, the opposite and adjacent sides of the angle in a 45°-45°-90° triangle are equal. Since tangent is the ratio of the opposite side to the adjacent side (tan0 = opposite/adjacent) , the value is 1.
To convert degrees to radians, use the formula:
Radians = Degrees × π/180
For 120∘:
120× π/180 = 2π/3
