Answer
$\color{blue}{\cos{0.6} \approx 0.8}$
Work Step by Step
To approximate the value of $\cos{0.6}$, look for the x-value of the point where the terminal side o the angle 0.6 radian crosses the unit circle.
Notice that for the given angle, the x-value of the point described above is around $0.8$.
Thus,
$\color{blue}{\cos{0.6} \approx 0.8}$
