Consider the parallelogram ABCD, with ∠ABC=60 and sides AB=3, BC=1. Let ω be the circle of center B and radius BA, and let τ be the circle of center D and radius DA. Determine the area of the region between the circumferences ω and τ, within the parallelogram ABCD (the area of the shaded region).
https://cdn.artofproblemsolving.com/attachments/5/a/02b17ec644289d95b6fce78cb5f1ecb3d3ba5b.png geometryparallelogramareas