What are the coordinates of a point on the unit circle if the angle formed by the positive x- axis and the radius is 45°? ?

On the unit circle, the radius is 1 and the trigonometric ratios are:

sin(angle( = y-coordinate / radius = y-coordinate / 1 = y-coordinate = y

cos(angle) = x-coordinate / radius = x-coordinate / 1 = x

Then:

y = sin(angle) = sin(45°) = √2 / 2

x = cos (angle) = cos (45°) = √2 / 2

=> (√2 / 2 , √2 / 2), which is the option A)