**Cos 60**

**Answer:**

1/2

In a right triangle, the cosine is the ratio of the adjacent side over the hypotenuse. Since 60 in a 30-60-90 triangle. We know the side opposite the 60 is root 3, the side opposite the 30 (or adjacent to the 60) is 1, then the hypotenuse is 2. Therefore the ratio of cosine is 1/2.