We have to verify if 4/5 and 5/6 are eqauivalent to 2/3.
We can verify this dividing the numbers by 2/3, and if we get the value 1, then they are equivalent. If they are equivalent, then the fraction can be reduced up to 2/3, and this division will give us the value 1.
We start with 4/5:
[tex]\frac{\frac{4}{5}}{\frac{2}{3}}=\frac{4}{5}\cdot\frac{3}{2}=\frac{12}{10}=\frac{6}{5}\neq1[/tex]4/5 is not a 2/3 ratio.
We continue with 5/6:
[tex]\frac{\frac{5}{6}}{\frac{2}{3}}=\frac{5}{6}\cdot\frac{3}{2}=\frac{15}{12}=\frac{5}{4}\neq1[/tex]5/6 is not a 2/3 ratio.