At a temperature of 10°c the percent relative humidity is r10, and at 40°c it is r40. at each of these temperatures the partial pressure of water vapor in the air is the same. using the vapor pressure curve for water that accompanies this problem, determine the ratio r10/r40 of the two humidity values.

the area between the graph and the t axis

wavelength divides in half and speed stays the same.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west