ratio of three to one であってます？
あってます。
9:3 - nine to three/9 to 3
3:1 - three to one/3 to 1
"9:3は、3:1です。"
the ratio of 9 to 3 is 3 to 1.
the ratio of 9 to 3 is equivalent to 3 to 1
equivalent to (=)
the ratio of 9 to 3 is equal to the ratio of 3 to 1
is equal to (=)
アメリカ合衆国 
