(20 14? In the square paper on the right, the side length of each small square is 1. After moving the length of BA in the direction of BA, the BC line is swept by it.
Solution: In Rt△AEB, AB=22+ 12=5.
In Rt△BCF, BC=42+22=25,
∴ After translating the line segment BC to the direction of BA by the length of BA, it can be seen that the quadrilateral ABCD is a rectangle.
∴ area rectangle swept by line BC =S ABCD=AB? BC=5×25= 10，