Answer:
Since, by the definition of exterior angle of an triangle,
b + 60° = 125°
⇒ b = 65°
By the angle sum property of triangle,
a + b + 60° = 180°
⇒ a + 65° + 60° = 180°
⇒ a + 125° = 180°
⇒ a = 55°
By the linear angle postulate,
60° + d + 90° = 180°
d + 150° = 180°
d = 30°
Again, by the angle sum property of triangle,
c + d + 90° = 180°
c + 30° + 90° = 180°
c + 120° = 180°
c = 60°
