问题
单项选择题
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
答案
参考答案：C
解析：
如下图所示，额外建的房子是图中的阴影部分：
[*]
设正方形地板的边长为a，额外建的房子伸出原房子b米，则根据题意可得：
a2=10,000→a=100米
ab=5,000→b=50米