The answer is BC = 8. The line segment EC is parallel to DF. This means they have the same measurement. DF is labeled as 4 units. So, EC = 4 units. On line segment EC, there are two lines going through the line. The same occurs on BE. These two lines mean that any line segment with the same number of lines going through it, equals the same length. Meaning that BE = EC. So, BE = 4 units. BE + EC = BC. 4 units + 4 units = 8 units.