Since the unit circle has a radius of 1 we know that r = 1 and that our angle is 60 degrees. Using sin and cos functions we can then find the x and y coordinates of point A. since [tex]cos(\alpha ) = \frac{x}{1}[/tex] and [tex]sin(\alpha ) = \frac{y}{1}[/tex] (where [tex]\alpha[/tex] = the angle)
[tex]A = (x,y) = (cos(a),sin(a))[/tex] because of the identity that cos(a) = x and sin(a) = y
Using the angle and the previously described identity we can find the coordinates with cos(60) = x = 1/2 and sin(60) = y = [tex]\frac{\sqrt{3} }{2}[/tex] to get A =(x,y) = [tex](\frac{1}{2},\frac{\sqrt{3} }{2})[/tex].
From here we can work backwards and find that BC = x = [tex]\frac{1}{2}[/tex] and that AC = y =[tex]\frac{\sqrt{3} }{2}[/tex] and finally we know that AB = r = 1 because it is a radius of the unit circle and must be 1.
-This probably isn't the way you were taught to solve this problem, but it is how we do it in physics and real-life.
