Doing the division.

To have the decimal you have to divide 3 by 8. ##3:8=0## and remain 3. Insert the dot and add a zero ##30:8=3## and remain 6. Add a zero ##60:8=7## and remain 4. Add a zero ##40:8=5## and no remain.

Then

##3/8=0.375## This is the decimal form.

The percentage is the decimal form multiplied for 100 with the sign ##%##. So it is

##3/8=37.5%##.