The magnitude of the vector is √(7^2+12^2)=√(49+144)=√193
The direction is α=arctan(y/x)=arctan(12/-7)≈-59.74 however this is relative to the negative x-axis so we add 180° to get the standard angle...180-59.74=120.26°
So the vector is √193 @ 120.26°