Radians and the unit circle

Converting

180° = π radians. Multiply by π/180 to go to radians, by 180/π to come back.

A circle of radius 1. The point at angle θ is (cos θ, sin θ) — so cosine is the across, sine is the up.

At π/6, π/4, π/3 the sines are ½, √2/2, √3/2 and the cosines are the same list backwards.