Answer:
b = 104°
Step-by-step explanation:
<DEA = <DAE (given)
Now,
<DEA + 142 = 180° (linear pairs)
<DEA = 180° - 142°
so, <DEA = 38°
Now,
<DEA + <DAE + b = 180° (sum of angles of triangle)
or, 38° + 38° + b = 180° (<DEA = <DAE)
or, b = 180° - 76°
so, b = 104°
