Chapter 7 - Trigonometry and Periodic Functions - 7.2 The Sine and Cosine Functions - Exercises and Problems for Section 7.2 - Exercises and Problems - Page 277: 14

$(-3.8,0)$

Since $180-2(360)=-540$, $-540^\circ=180^\circ$. It is known that the coordinate on the $x$-$y$ plane for an angle $\theta$ from the horizontal and a radius $r$ is $(rcos\theta,rsin\theta)$. Using $r=3.8$ and $\theta=180^\circ$ gives a point $$(3.8cos(180^\circ),3.8sin(180^\circ))=(-3.8,0)$$