If there are 3 variables interacting, and you want to investigate how ONE variable affects ONE OTHER variable, what must you do with the 3rd variable?

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

conservation of mass

mass before something happens = mass afterwards