Physics displacement?

A wants to see his friend B. The house of B is located at the side of a street perpendicular to the street where (at the side of this street) A's house is located. A then drives 300 m towards north through his car to reach the crossing of the mentioned streets. He then drives 400 m towards east to finally reach B's house. But B is at C's house which is located at the side of the same street as that of B's house. A then drives east until he reached C's house. If the total displacement magnitude of A from his house is 700 m, how far is C's house from that of B? Assume that the two houses are located at the same side of the street.