Question 731879
if {{{1kg}}} cost ${{{9}}} then

{{{xkg}}} cost ${{{4}}} 
 
do it as a proportion: {{{1kg:9dollar=x:4dollar}}}

{{{1kg*4dollar=x*9dollar}}}

{{{1kg*4cross(dollar)=9x(cross(dollar))}}}

{{{(4/9)kg=x}}}

{{{0.44444kg=x}}}