The cosine ratio is the side adjacent to the reference angle over the hypotenuse. Angle T has a side opposite of length 68, and the hypotenuse is 85. Therefore, the cosine of T is 68/85. That gives us a decimal of .8. It's very important that the ratio of sin and cos are decimals less than 1 but greater than 0. If you try to take the inverse cosine of, say, 1.4 on your calculator you will get an error message. That's because sin and cos oscillate between 1 and -1 on the graph and do not exist higher or lower than that.