Due to the properties of a Isosceles trapezoid, [tex]\overline{WY} =\overline{ZX}[/tex].
Therefore, [tex]8a - 3 = 19[/tex] since [tex]\overline{WY} = 8a - 3[/tex] and [tex]\overline{ZX} = 19[/tex].
[tex]8a - 3 = 19[/tex]
[tex]8a = 22[/tex]
[tex]a = 2.75[/tex]
