The terminal side is which defines the angle when the angle is drawn in standard position.So, the other side is on the x-axis. Then, you can draw a triangle with adjacent leg x = 12, opposite leg y = 5 and hypotenuse = sqrt (12^2 + 5^2 ) = 13. So, the cosine of the angle is x-coordinate / hypotenuse = 12 / 13. That is option b. 12 / 13. The cotangent, is the inverse of the tangent => cot = adjacent leg / opposite leg = x-coordinate / y-coordinate = 12/15. That is option c. 12/5. Hope this helps!