First I added 6 and 13 to get 19 then i said that they were going straight down to measure the sides so that means you need to multiply 5 times 2 and get 10 but the sides are tilted so if the sides are tilted then you need to add a half more for each because they are actually a little bit bigger then what they are saying so now you have 5 1/2 plus 5 1/2 and that gets you to 11 and 11 plus 19 is 30
