The heat index combines air temperature with relative humidity to give an idea as to how hot it "feels" outside, much the same way that the wind chill index links cold temperatures and wind speed. the national weather service uses the following equation to determine the heat index:
hi=-42.379+2.049t+10.143r-0.225tr-( 6.838*10^-3)t^2-0.0548r^2+
(1.229*10^-3)t^2r+(8.528*10^- 4)tr^2-(1.990*10^-6)t^2r^2
where t is the air temperature in degrees fahrenheit and r is the relative humidity (ie. r=%% if the relative humidity is 55%). the equation is valid only for air temperatures above 80 degrees fahrenheit and relative humidities above 40%.
23.) on a hot humid summer day, the temperature reaches 95 degrees fahrenheit with a relative humidity of 75%. calculate the heat index to the nearest degree.
24.) write an equation that gives the heat index hi for any temperature t given a relative humidity of 100%. round your coefficients to 3 decimal places.
25.) on a warm day both the air temperature and the heat index are 85 degrees fahrenheit. what is the relative humidity? round any coefficients to 3 decimal places and give your answer to the nearest percent.