A circular table has a glass center with a diameter of 4x inches, which is surrounded by a metal ring with a width of 2 inches. In terms of x, what fraction of the table's surface is made up by the metal ring?
-
A$${1}\over{x+1}$$
-
B$${1}\over{x}$$
-
C$${x}^{2}\over({x+1})^{2}$$
-
D$${2x}+1\over({x+1})^{2}$$
-
E$${x}\over{x+1}$$
显示答案
正确答案: D