Measure 45 minutes with 2 strings

You are given 2 strings and a lighter. It takes one hour to burn each of the strings. These two strings are unequal in length and unequal in composition. For example, say one of the strings is 6 inches long, it could take 59 minutes to burn the first inch, and then 1 minute to burn the remaining 5 inches, and the other is 10 inches long, and it takes 33 minutes to burn 5.5 inches and 27 minutes to burn the remaining 4.5 inches. How do you measure 45 minutes?