experience I learned that my children knew how to find the perimeter
and given the perimeter, they could also find the missing side. But when
testing came, the shapes were awkward, unusual, and just plain boring. A recipe for disaster, but a skill they really needed. I have created many area and perimeter resources and this free worksheet is available at my blog. Use it for review, homework, group work or an assessment.
I also explain an excellent tip to make sure they consistently get the exact number of sides. Visit my blog today to get this printable for your files.