Refer to the figure below, in which $m(\angle 1)+m(\angle 3)+$ $\mathrm{m}(\angle 4)=180^{\circ}, \angle 3 \cong \angle 4,$ and $\angle 4 \cong \angle 5 .$ Find the
measure of each angle.
a. $\angle 1$
b. $\angle 2$
c. $\angle 3$
d. $\angle 6$
(figure not copy)