# Say "Yes" to the Dress

### Thursday February 16, 2017

###### •  crafts • math education •  mathematics •  sewing •  UMGC •

One thing I am sure my students hate is that I don’t give extra credit. I’ve talked about this before, and there is no reason to rehash them. But I do like to add something when I can use extra credit to push their boundaries, or something neat.

Last semester, while teaching precalculus, Nina decided to make a dress for Ducky. She made a small math error when she first did the calculations and the results were clearly incorrect at the end. Fortunately, we caught that before she started working from them, and we got it together on round two. But a problem was born:

Everyone, I have created a surprise extra credit problem. Right now, Nina (my lovely wife) is at the dining room table with a pad of paper and bolt of what can only be described as Elsa blue fabric. She is making a holiday dress for our terrible daughter, known as Ducky. Ducky is 4 and, therefore, the holiday dress project evolved into a Frozen ballgown, hence the color. If you have talked to a little girl in the last 3 years, you’ll understand.

So we have a measurement of 23 inches on the waist. Additionally, the length of the skirt section of the dress is to be 17 inches (“all the way down to my toes!”). The challenge to you, should you choose to accept it, is to model the skirt section of the dress. Determine how much fabric is needed, and what the cuts look like. Some information necessary to solve this problem may be missing. That’s part of the challenge.

Good luck.

P.S. Our initial model was incorrect, and while I was a math major, she was also nearly one (three classes short). And we still had to do this twice. So take it easy and enjoy.

It wasn’t worth a lot of credit, but I got 4-5 responses. Two of them, however, were outstanding. With their permissions, I am posting them here. They both embraced the challenge by figuring out first what the problem was, then deciding how to address the known unknowns, and finally solving the problem. And that problem solved wasn’t the one I gave, but rather one we created through a shared understanding of what mattered and what didn’t.