The vectors a and b represent two forces acting at the same point, and $\theta$ is the smallest positive angle between a and b. Approximate the magnitude of the resultant force.
\begin{aligned}
&\text { (a) } 70 \mathrm{Ib}, 320^{\circ}\\
&\text { (b) } 40 \mathrm{lb}, 30^{\circ}
\end{aligned}
(a) $70 \mathrm{lb}, 320^{\circ}$
(b) $40 \mathrm{lb}, 30^{\circ}$