In the triangle below, 4/5 represents which ratio?

sin (C)

Explanation:
In a right-angled triangle, special trig functions can be applied. These functions are as follows:
sin (theta) = 

cos (theta) = 

tan (theta) = 

Now, let's check the triangle we have:
We have two options:
First option:
5 is the hypotenuse of the triangle
4 is the side adjacent to angle B
Therefore, we can apply the cos function:
cos (B) = 

Second option:
5 is the hypotenuse of the triangle
4 is the side opposite to angle C
Therefore, we can apply the sin function:
sin (C) = 

Among the two options, the second one is the one found in the choices. Therefore, it will be the correct one.

Hope this helps :)