Thursday, May 22, 2008

A Random Sunday

Last Sunday morning I woke up super late (after 9!) and lay in bed thinking about the formula to find the ratio of the diameters of two concentric circles such that one is exactly twice the area of the other. Not a hard formula...most of my time was spent doing out the square root of 2 to several decimal places in my head. Eventually I resorted to paper.

As I was busy drawing circles of diameters roughly 30 and 42 centimeters on my bathroom mirror with whiteboard markers, the phone rang. It was my friend Ssabu, the drum teacher.

"Hey! What are you doing now?"

"Uh..." (I decided not to try to explain.) "Er, nothing much. Why?"

"Good! I want you. I--I want see you. Today--sports day."

Sports day. I've witnessed enough of these recently on the sand (!) playing field near my classroom building to know that everybody's doing it. The matching T-shirts, the group cheers, hell-bent trios practicing some kind of four-legged race. "Okay. Uh, who's playing? Other clubs?"

"No other clubs. Just Maltuh." (Maltuh is our music group.) "And--many people. Anybody."

Sounded like as good an offer as I could hope for. "When does it start?"

"Now. Already--start. Meet me--11:00, international center, okay? Wear sports clothes."

Well, duh.

Half an hour later, clad in my new ponytail and pajama bottoms that I hoped looked enough like sweatpants, I jogged up to the international center, where I was met by a couple team members in a car and ferried literally 200 yards to a small basketball court out behind one of the older buildings. A couple dozen young to middle-aged people and half a dozen of their progeny were facing off wearing matching towels in garish pink and orange.

I picked my team color out of a box and went to join the fray. I liked this dodgeball game, where my job was to defend my partner, holding onto my shirttails, from getting hit by people around the perimeter of the basketball court and to try to help my own team members peg those on the opposite side. It felt kind of like dodgeball-meets-lion dancing.

By the time I excused myself for drum practice in preparation for the big July concert (which my drum teacher tried, ironically, to convince me to skip) I was a little relieved to go--not that it wasn't fun, but the schedule for the day was posted on the wall and stretched on until 6 pm. I wasn't sure I would have held up that long. As I left, I waved goodbye to the shy elementary school girls who'd been pushed into chatting with me by their parents, and successfully parried a come-on from one of the older men (which means I got everyone to laugh instead of pouting in my humiliation).

Just goes to show that when you wake up in the morning thinking about math, you never know what may happen.

4 comments:

Michael5000 said...

Arbitrary math dorkiness! I KNEW I liked you.....

Well done on sports day. "Dodge Ball meets lion dancing" = awesome! The world needs more of that....

Anonymous said...

Ugh. Feeling dumb now. I tried to solve what you put forth, and can't do it. And I'm doing the GRE in a month. I'm going to bomb the math portion.

Heatherbee said...

This is my solution and I do not claim it to be infallible. My math is rusty.

Let r=the radius of a circle with area C
Let s=the radius of circle with area D such that D = 2C

D = π s2 = 2 C = 2 π r2
s2 = 2 r2
s = √2 r

s is pretty damn close to 1.413 r

(especially dealing with a ruler, string, and two whiteboard markers on your bathroom mirror)

Hope that helps. Don't sweat the GED. Buy beer for some high school students and maybe they'll let you look at their textbooks.

Heatherbee said...

Agh! My r-squared became r-two.

Here's the formula again, uglier but more accurate.

D = [pi] [s squared] = 2 C = 2 [pi] [r squared]

[s squared] = 2 [r squared]
s = [square root of 2] r