2.比例4:9=20:45中45加上5,为使比例成立,9应该加上( )
0 137053 137061 137067 137071 137077 137079 137083 137089 137091 137097 137103 137107 137109 137113 137119 137121 137127 137131 137133 137137 137139 137143 137145 137147 137148 137149 137151 137152 137153 137155 137157 137161 137163 137167 137169 137173 137179 137181 137187 137191 137193 137197 137203 137209 137211 137217 137221 137223 137229 137233 137239 137247 199269
| A. | 5 | B. | 1 | C. | 3 |