I’m teaching a geometry course at FPU this semester. I taught the same course three years ago, but my philosophy and practice have shifted so significantly in that span that I’ve scrapped what I used the first time around and am in full create-and-curate mode.

With that in mind, I’ve been frequenting Geoff Krall’s fantastic curriculum maps rather, um, frequently as of late. My latest joy-filled find: Don Steward’s Complete the Quadrilateral (via Fawn Nguyen).

Inspired by these posts—and a separate domino-style activity shared by Mike Chamberlain at a common core workshop last semester—I spent a good portion of my three-day weekend turning the complete-the-quadrilateral task into 21 dominos of self-checking goodness.

Set Up

Teachers, print this…

…and use these…

…to get a stack of these…

…which you’ll shuffle and put in one of these…

…and hand out to groups of these:

How to Play

Working in groups of 2-4, students will:

• Join dots to complete the indicated quadrilateral on each domino (Multiple possibilities? Maximize the area!)
• Determine the area and perimeter of each figure
• Connect the domino chain, from start to finish

Just to clarify the whole “domino chain” bit, each domino contains one answer on the left (to a previous card’s question) and one question on the right (with an answer to follow on the next card). I’m fairly certain that last sentence doesn’t make any sense, so… “Hey-look-a-picture!”

Solutions

If you need a hand with completing the quadrilaterals, check out the source, or even the original source. (Note that I removed four problems—Fawn’s #9-11 and 14, due to identical figures mucking up the uniqueness of my domino chain—and that my final problem matches Don’s, not Fawn’s.) For help with the area, perimeter, and domino sequence, note that my handouts contain the dominos in order (reading one column at a time, from top to bottom):

Variations

The teachers in my geometry class served as guinea pigs for this revamped version of the activity, and after a debriefing discussion, I think it would be wise for me to create a few variations to allow for more students to participate without becoming too overwhelmed/frustrated. (Translation: The task took a very long time, and with the four required steps—complete the quadrilateral, find the area, find the perimeter, match the domino—I’m afraid student interest will fizzle out as frustration grows.)

Here are several I’m wondering about (including one I’ve already added):

• Split the deck into two groups of 10 dominos (Set A, a bit easier; Set B, more challenging), allowing for three levels of difficulty to differentiate between or within classes (Set A only, Set B only, Sets A and B)
• Reduce the deck to 10 dominos, remove perimeter from consideration (if the self-checking domino action is to stay in tact, I think I should make sure I have 10 distinct areas)
• Same as #2, but remove area from consideration (not sure if I would then make the rules “maximize perimeter” or if that’s just too awkward)

Request for Feedback

There’s a lingering fear in my mind that I took a great activity and ruined it. If you think that’s the case (or not the case), I’d love to hear why in the comments. Also, if you have any other suggestions for tweaking the length of the activity without losing its original challenge or appeal, let me know.