Archer and Marilynn are in the same class. Archer takes a sheet of paper and cuts out a triangle whose longest. side is 1 inch. Marilynn cuts out a similar triangle whose longest side is 1.5 inches. Archer cuts out another similar triangle whose longest side is 2 inches and Marilynn responds with a similar triangle whose longest side is 3 inches. They continue with this pattern until the end of the class period when Marilynn has a triangle with perimeter of 36 inches. What is the perimeter of Archer's triangle at the end of the class period?​