The heat index is calculated using the relative humidity and the temperature. For every 1 degree increase in the temperature from 94 degrees Fahrenheit to 97 degrees fahrenheit at 75% relative humidity, the heat index rises 4 degrees Fahrenheit. On a summer day, the relative humidity is 75%, the temperature is 94 degrees Fahrenheit and the heat index is 124 degrees Fahrenheit. Estimate the heat index when the relative humidity is 75% and the temperature is 100 degrees Fahrenheit. Use a function to justify your answer