I hated math until I finished high school and no longer had to do it on a regular basis. When I do math now, it is on my own terms, no teacher is looking over my shoulder and making me feel self-conscious. I was never *that* bad at math, but I was generally pretty slow about it. Now that I'm not timed anymore, it doesn't even matter. So these days math and I get along pretty well.
This is especially good when it comes to knitting, as we often deal with math. I do all sorts of division and multiplication these days. This weekend I ran into a particularly cool math problem, and I thought I'd share it with you.
A knitter wants to make the Cap Shawl from Victorian Lace Today. This shawl calls for 1700 yds of yarn to make a shawl 74" across (radius: 37"). The knitter finds a skein of Merino Oro laceweight with just 1375 yards. How big a shawl can she make?
To solve: the first step is to figure out the area of the pattern shawl, so we know how far 1700 yards gets us. (we are rounding for sanity's sake)
A=π * 37^2
A=π * 1367
Ok, so 1700 yards makes 4300 square inches of lace. Now we need to find out how many square inches of lace (x) we can make with 1375 yards of yarn. My algebra here gets kind of ugly, but bear with me.
(4300 in^2)/(1700yds)= x/(1375 yds)
Remember your algebra steps! Multiply across...
1700x = 4300 * 1375
1700x = 5,912,500
x = 5,912,500/1700
x = 3478 in^2
So the new shawl will have an area of 3478 square inches. What's the radius of our new shawl?
A = πr^2
3478 = πr^2
r^2 = 3478/π
r^2 = 1108
(Not even gonna attempt the square root sign)
r = 33 in
So the new shawl will be 66" across, which I think is perfectly acceptable, as I am 66" tall.
Once I've made a swatch of the pattern I'll figure out how many rows I need to leave off in order to reduce the radius by 4". I'll edit the lace pattern from there (more math!)
So, wasn't that fun? Here's something even more fun, for those of you who've made it this far: this yarn ($16.50) was my first wedding-related purchase. 3478 square inches of knitting from now, I'll have my veil done!