Since DA is the diameter the formed angle equals 180
since DZC=2x
then
[tex]180=DZC+CZB+BZA[/tex][tex]180=(2x)+(7x-4)+85[/tex][tex]180-85+4=9x[/tex][tex]x=\frac{99}{9}[/tex][tex]x=11[/tex]
since x= 11
then the measure of the angle CZB is given by
[tex]7(11)-4[/tex][tex]mCZB=73[/tex]
measure of the angle CZB is 73°
Correct answer option D
73°
