A geometry construction problem I could actually do!

This is a geometry problem someone sent me on twitter. You really don't need anything more complicated than understanding isosceles triangles and angle sum in a triangle = 180°, but the solution does take some creativity with construction. In triangle ABC, AB=AC, and D is a point inside the triangle such that AD=BC, ∠BAD = 10°, and ∠CAD = 30°. Find ∠BDC. I've added this to the AMC senior division playlist even though it's not from the AMC, because it's of a similar difficulty level.