Extend the ratios of the numbers so that both members of the ratio become integers.
Then reduce if necessary.

a) [[$ 2 \displaystyle\frac {1} {2} : 1 \displaystyle\frac {1} {2} $]] = :

b) [[$ 1 \displaystyle\frac {1} {2} : 5 \displaystyle\frac {1} {4} $]] = :

c) [[$ 5 \displaystyle\frac {3} {4} : 1 \displaystyle\frac {2} {3} $]] = :

d) [[$ \displaystyle\frac {2} {3} : 0,75 $]] = :

e) [[$ 0.25 : 3.5 $]] = :