So what do a dragon and knights and ladies of the Middle Ages have to do with math?

Listening to the names of the characters in a play performed by Desert Star Community School in Cornville for Sedona Charter School students at the Sedona Public Library offers a clue. The hero, Sir Cumference, is a knight who has many math adventures. His wife is Lady Di of Ameter. They have a son named Radius who has a friend named Vertex the Line-Hearted. The names are a play on words using math terms written in a series of children’s educational books about math by Cindy Neuschwander and Wayne Geehan. Currently there are six books in the series.

Sir Cumference refers to the circumference or the distance around a circle; Lady Di of Ameter portrays the diameter or the distance across a circle. Radius and Vertex also relate to circles.

The play the sixth-grade students presented, complete with a hand-painted castle, costumes, painted-on beards and mustaches, a large dragon head and a few attempts at an English accent, was from “Sir Cumference and the Dragon of Pi.”

“The class learned about pi this year as part of their algebra class, so we did this particular play. However, we do have all six books in our classroom,” teacher Nina Bingham said. “We put together this play and wanted to present it to an audience, so we called Sedona Charter. They were excited to be our audience.”

Pi is a mathematical constant whose value is the ratio of a circle’s circumference to its diameter. Pi is an irrational number since the pattern of its decimal representation never repeats: 3.1415926535…, and so on. Pi is most often represented by the symbol π.

The idea behind the books and the play is to show math can be fun; it’s a way to act through a story while learning math concepts. Children who don’t like math can embrace the story and get the math, Bingham said. “We like using the arts to teach and learn.”

Before the play began, Bingham asked how many in the audience liked math. Nearly half raised their hands. About one-third said they had read Neuschwander and Geehan’s books. She also introduced the characters and asked the students to define the math terms. Bingham also narrated the 10-minute play.

After Sir Cumference is accidently given a potion for a bellyache that turned him into a fierce dragon, Radius frantically tries to find the correct potion to turn him back to his human self, but also has to figure how much of the potion to give him. It had to be exact or his father would remain a dragon, but not for long. Knights are out to find the dragon and kill him.

Radius goes to help his cousin Lady Fingers who needed assistance to finish placing the last part of the crust on her last pie. Radius saw the number of pieces that were needed to complete the circumference of the pie and noted the relationship between the circumference and the pieces that extended from one side of the pie to the other. He rushed back and figured what he needed of the potion was three and one-seventh dose — pi.

Radius cures his father just as the knights rush into the castle with their swords held high to slay the dragon.

“This is a really fun way to learn math, especially for kids like me who have ADHD [attention deficit hyperactivity disorder],” Damian Huff said as he slipped off his red knight’s cape.

Bingham said she has found many children like to learn through activity and drama because it’s fun.

“Whatever you learn with joy, you learn forever,” she said.