Given is a right triangle.
We know that the ratio of cosine is defined as "adjacent" over "hypotenuse".
With respect to the angle given, we see that
• x is the adjacent side
,
• 7 is the hypotenuse
Thus, we can write:

Now, we can cross-mutliply and figure out the length of "x". Shown below:

Answerx = 5.73