A vector of length 20 is oriented at an angle of 120° from the positive x-axis. find the x and y coordinates of the end of the vector

Refer to the figure shown below.

The reference angle is 180 - 120 = 60°.

Note that in quadrant 2, sine is positive but cosine is negative.

The x-component of the vector is

-20*cos (60°) = - 10

The y-component of the vector is

20*sin (60°) = 17.32

Answer: (-10, 17.32)