Two segments of lines or two angles are congruent if the have the same length and the same measure, respectively. In a parallelogram, a geometric figure which opposite sides are parallel, opposite sides are congruent and opposite angles are also congruents.
In this case CD is opposite to AB, so they are congruent and have the same length. Since the segment AB measures 2a and the segment CD mesures 34, then we have the equation
[tex]\begin{gathered} 2a=34 \\ a=\frac{34}{2} \\ a=17. \end{gathered}[/tex]Similarly, the angles A and C are congruent since they are opposite, so their measurement is the same. Since the angle A measures 8b and the angle C measures 112, then we have the next equation
[tex]\begin{gathered} 8b=112 \\ b=\frac{112}{8} \\ b=14 \end{gathered}[/tex]
