Answer: 72
Because the picture shows that there's a 90 degree angle in the bottom. We know that the bottom triangle is a 45-45-90 triangle. So the length of one side is 18 because a 45 45 90 triangle has two sides that are equivalent (x) and one side that is x
. So now that we know the length of one side is 18, we know the lengths of all 4 sides. Adding them up ( 18 + 18 + 18 + 18) gives 72, which is the perimeter.