杭州交通信息网小人简笔画教学视频:Math problem
来源：百度文库 编辑：杭州交通信息网 时间：2024/05/05 01:49:33
a pond 100 feet in diameter is surrounded by a circular grass walk which is 2 feet wide. The number of square feet of grass on the walk is.....
3.14x((100+2x2)/2)^2-3.14x(100/2)^2