When converting a percentage to a decimal jump 2 times to the left from the percent sign. Because percent means out of 100, it is basically a division problem. You are dividing the percent as it is the numerator of the fraction and the denominator is 100. Essentially what happens is you are turning the percent sign to a decimal and jumping it twice to the left twice.
A ratio is a comparison of two quantities using division. It is simply a fraction. A proportion by definition is two equivalent ratios. Which means 2 equal fractions.