Gifted Issues Discussion homepage Forums General Discussion Triangle question - 2nd grade

This has to be ridiculously simple, and I'm just overthinking it. DD7 has an Everyday Math page that asks her to draw a triangle that is 4cm on all sides.

I can do it with a compass, no problem. I showed her that. But that can't be what they are expecting her to do. Is there something obvious that I'm overlooking? She had no idea how to do it, and said they hadn't learned that, which may or may not be true -- she gets really silly about math things and doesn't pay a lot of attention sometimes.

FWIW, I have a 2nd grader and I'd guess that they want her to "rough" out an equi triangle with sides measuring close to 4 cm and labeled as such. Just a simple eyeballed one.

Is this one of those problems that you have to do in five different ways?

Gawd, I hope not! I can only think of the one way. Although, as mama says, it could be just a simple eyeball thing, so that's two.

You can do it without a protractor, and I think it's likely they are just having the kids figure out a way to do it, either by eyeballing it or by doing something like marking the correct amount of cms on three pieces of scrap paper and holding together to make the outline of the triangle etc.

polarbear

How about drawing a straight line 4cm long. Draw a line perpendicular (eyeball) to this line from the midpoint(2cm). Make this line really faint. Then keep the ruler at one end point on the horizontal line and keep moving it till it meets the vertical line and measures 4 cm. then complete the triangle. Wouldn't that work? Oh boy, I better brush up on my elementary math.

Not an easy problem. I wonder how my perfectionist kid, DD16, made it through Everyday Math. She did so without complaining, and even now she doesn't think it was a bad experience. DD9 is in her first year of public school and hates Everyday Math. Complains they don't spend enough time on any one topic and they throw random stuff in that they haven't learned yet (such as primes). Previously she was in a school that used a European math text (French). While the French do "spiral" in math, they spend more time on each topic and the explanations are much better than I have seen in American texts.

To do that problem properly, you need to know some geometry. I'd call it an 8th grade problem.

It's interesting, though, that this thread has already come up with 5, count'em, five, significantly different ways to do the question (ruler and compass construction; purely by eye; use a protractor and measure; use the perpendicular bisector of a side to help guide the eye; manipulate edges). Between them these bring out a lot of important geometry, especially that you can use "equal angles" or "equal sides" in this case (in more advanced geometry, a lot of the art is knowing when to go after angle, when sides, and when you can play them off). At the risk of making everyone hate me, I think this suggests it's quite a good question! ETA with a high ceiling (fully understanding all the methods and their pros and cons) and low floor (gaining a basic understanding of what an equilateral triangle is), as the educationalists say - the only pitfall really is kids being too scared to have a go. ETAagain infinitely better as guided exploration in class than as homework, though!

I agree, and the biggest pitfall for poorly implemented exploration type math seems to be when the teacher expects each student to list exactly 4 specific methods of achieving the result. Undermines the whole thing.

I wonder if they circle back on the question in the next class and list the different approaches and the thoughts behind those approaches.

I don't know if the CC math will be any better, but our school currently uses Everyday Math, and I figure it couldn't be any worse!
In third grade, they drew rays and they had to name them. (I thought, name it like AB or something, from the points on the ray).
My son labeled one "David" and another "Tony." He said those were his best friends' names!
I thought he was goofing around but that was what the Everyday Math publishers wanted- a way for children to "get comfortable" with math!!