the answer is 140
CB + CD=180
DA +BA=180
DA=CB
CD=BA
[tex]16z + 12 +2( 2z + 4 )= 180 \\ 16z + 12 + 4z + 8 = 180 \\ 16z + 4z = 180 - 12 - 8 \\ 20z = 160[/tex]
[tex]z = \frac{160}{20} = 8[/tex]
the value of z is 8
so BA is
[tex]16 \times (8) + 12 = 128 + 12 = 140[/tex]
good luck
