Rates of obesity have been steadily rising in the United States over the past two decades. This is a major health concern because obesity is a risk factor for a number of chronic illnesses including type II diabetes, heart disease, and high blood factor. But how do you classify someone as being obese? According to the (Centers for Disease Control) CDC, "Body Mass Index (BMI) is a number calculated from a person's weight and height. BMI is a reliable indicator of body fatness for people."

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In particular, BMI classifies an adult person (20 years old or older) into one of the following categories,

The equation used to calculate BMI is given by the rational function,

where w is a person's weight in pounds and h is a person's height in inches.