Dimensional analysis is used to convert units. It's the process of analyzing units to decide which conversion factor to use. It's used by multiplying units by conversion factors, rates equal to 1.
The first step to solving proportions is cross multiplying. For example, we are told to solve the proportion 13/3 = x/9. We cross multiply 13 •9 and 3 • x. Remember, the equal sign does not go away, so don't forget about it! The equation is now 3x = 117. We need to isolate the variable so we do 3x ÷ 3, which is x, and 117 ÷ 3, which equals 39. We now know that x = 39.
