A warehouse had a square floor with area 1
题型：单项选择题
问题：
A warehouse had a square floor with area 10,000 square meters. A rectangular addition was built along one entire side of the warehouse that increased the floor area by on-half as much as the original floor are-a. How many meters did the addition extend beyond the original building ？（）
A．10
B．20
C．50
D．200
E．500