The angle made by the vector is
such that
![\tan(\theta) = (18.4\,\rm m)/(-28.7\,\rm m) \approx -0.6411](https://img.qammunity.org/2023/formulas/mathematics/high-school/k63a78gdy3usnxikehwuj8rjapv6qtusag.png)
Before taking the inverse tangent of both sides, recall that
returns a number between -π/2 and π/2 radians, or -90° and +90°. The vector in the diagram clearly makes an angle between 90° and 180°, however, so we use the fact that tangent has a period of π rad / 180° to write
![\theta \approx \arctan(-0.6411) + 180^\circ n](https://img.qammunity.org/2023/formulas/mathematics/high-school/neobepdtwwm7w5n7gk9qh5f0ztvbi059z3.png)
where
.
Now,
![\arctan(-0.6411) \approx -0.5701 \,\mathrm{rad} \approx -32.6639^\circ](https://img.qammunity.org/2023/formulas/mathematics/high-school/qu3n94vlmbh01ha6u7bpr6e3tpvdhlcj1b.png)
Add 180° to this to recover the correct angle.
![\theta = \arctan(-0.6411) + 180^\circ \approx \boxed{147.34^\circ}](https://img.qammunity.org/2023/formulas/mathematics/high-school/lb7ug6h3vnds3o3y6bp0loljkm4gxargk0.png)