Answer:
∠ BAD = 43°
Explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
∠ BAD is an exterior angle of the triangle, thus
∠ B + ∠ BCA = ∠ BAD , substitute values
3x - 10 + 5x + 9 = 6x + 10 , that is
8x - 1 = 6x + 10 ( subtract 6x from both sides )
2x - 1 = 10 ( add 1 to both sides )
2x = 11 ( divide both sides by 2 )
x = 5.5
Thus
∠ BAD = 6x + 10 = 6(5.5) + 10 = 33 + 10 = 43°