问道GRE For a project,a square piece of cloth is folded in half and swed together to form a rectangle that has a perimeter of 36 centimeters.what was the area in square centimenters of the piece of cloth before it was folded.这个题我得出的答案是48,正确的答案是144,
问题描述：
问道GRE
For a project,a square piece of cloth is folded in half and swed together to form a rectangle that has a perimeter of 36 centimeters.what was the area in square centimenters of the piece of cloth before it was folded.
这个题我得出的答案是48,正确的答案是144,
答
正方形对折以后成长方形，设正方形边长为a，
长方形周长为：a+a+a/2+a/2=36，a=12；
正方形面积为：a^2=144
答
他求得是未折之前正方形面积
折成长方形后 周长36 说明正方形原来边长12
所以面积是144