Solution: First, take the midpoint of AC as O, and then take BO. When intersecting with O, the perpendicular lines of BC and AB intersect with BC and AB at points E and D respectively. Obviously, BO bisects ∠ ABC ∠ OBA = ∠ OBC = 30 ∴ OE = OD = OB/2 = h/2: the diameter of the circle is equal to the height h of △ABC, and the tangent point is d and e ∴ OE = of.