Starting with the proportion:
[tex]\frac{12}{?}[/tex]Since it should be equal to 4/3, notice that if we divide both numerator and denominator by 3, then we should get 4 and 3 respectively:
[tex]\frac{12}{?}=\frac{12\div3}{?\div3}=\frac{4}{?\div3}=\frac{4}{3}[/tex]Therefore, ?÷3 is equal to 3.
Which number is equal to 3 when we divide it by 3?
That number is 9. 9÷3=3
Therefore, ?=9.
