How do you get from 3 meters to 5 meters? Add 2 meters. How do you get from 5 meters to the next measurement? Add 2 meters again.
Start at 3 meters, add 2 to get 5 meters, and so on. Continue this pattern until you have all 6 side lengths. The last one represents the length of the longest side.
Here we're working on an "arithmetic sequence."
