The base of the ladder should be placed so that it is one foot away from the building for every four feet of hight to where the ladder rests against the building. This is known as the 4 to 1 rule.
9 and 1/4 are both rational numbers (which are numbers that can be represented in a fraction; 9 can be represented as 9/1) And since it equals to 9/4 (or 2 1/4) the product is also a rational number.
