At Phoenix International Airport (PHX), the observed surface temperature is 45 °F and the dew point temperature is 10 °F. Calculate the relative humidity at PHX using Table 1 from chapter 4. Explain your relative humidity calculation, by choosing values from the drop down lists that correctly complete the statement below: To calculate the relative humidity, I [ Select ] a vapor pressure of [Select] mb by a saturation vapor pressure of [Select ] vmb to get a relative humidity of [ Select ] v %.