the width of a rectangle is 7 cm shorter than the length .if

题意：一个矩形的宽度比长度短了7厘米。如果矩形的周长是38厘米,得到(a)宽度　(b)长度(c)矩形区域设length长=x,则width宽=x-7perimeter周长=2（x+x-7）=38。解之,得x=13the width宽=the length长-7=13-7=6(b) 由（a）知the length长=13(c)the area of the rectangle 面积=the width长×the length宽＝13×6＝78