Question 28391
Here's one way to tackle problems like this:

x/100 = is#/of#

Explanation: 

The x is the percentage you are trying to find.
The is# is taken from the problem, which in your case, it says" ...19.8 is what..." So 19.8 is the is#
The of# is also taken from the problem, which in your case, it says "...what percent of 36." So 36 is the of#.

So we have: 
{{{x/100 = 19.8/36}}} Now multiply both sides of this equation by 100.
{{{x = 100(19.8)/36}}}
{{{x = 1980/36}}}
{{{x = 55}}}

The answer is:
19.8 is 55% 0f 36