9514 1404 393
Answer:
34°
Step-by-step explanation:
It should be fairly intuitive that the two smaller angles add to give the value of the larger one. (Even if it's not, the angle sum theorem tells you this is true.)
∠ABC + ∠CBD = ∠ABD
∠ABC + 30° = 64°
∠ABC = 34° . . . . . . . . . subtract 30° from both sides of the equation
