Answer:
∠ b = 108° , ∠ d = 72°
Explanation:
(a)
the sum of the 3 angles in a triangle = 180° , that is
∠ a + ∠ b + ∠ c = 180°
25° + ∠ b + 47° = 180°
∠ b + 72° = 180° ( subtract 72° from both sides )
∠ b = 108°
(b)
the exterior angle of a triangle is equal to the sum of the 2 opposite interior angles , then
∠ d = ∠ a + ∠ c = 25° + 47° = 72°