Find the measures of eaf dae and cad

You have to build an equation to find the answer,

angles in a straight line add upto 180° 
so your equation would be,

12x+30°=180°
      -30    -30
=12x=150°
   ÷12  ÷12
=x=12.5°

now find the measures of the angles by using 12.5 as x.

angle EAF= 2x
                 =2×12.5
                 =25° degrees

angle DAE= 4x
                 =4×12.5
                 =50°degrees

angle CAD=6x
                 =6×12.5
                 =75°degrees

check,
30+25+50+75=180°degrees

hope this helps