Prerequisites: Trig 1001, Geometry 1001

April 12, 2019 9:25 AM

Catriona Shearer: Maths teacher and fan of geometric puzzles.
posted by Think_Long (11 comments total)

20 curated puzzles plus an interview at Math With Bad Drawings
posted by J.K. Seazer at 9:47 AM on April 12, 2019

I want to be able to solve these. I loved geometry when I took it as a sophomore in 1979, and I liked all the parts of math than involved doing proofs based on theorems--we had a year of analysis before calc in my high school, and I loved it.

I've been thinking about taking up math again as a hobby. Now I have a goal to work toward.
posted by Orlop at 10:14 AM on April 12, 2019 [2 favorites]

Damn I thought I was smart. Guess not.
posted by M-x shell at 11:43 AM on April 12, 2019

I had to stop following her on Twitter, that's how good these are.
posted by w0mbat at 12:09 PM on April 12, 2019 [1 favorite]

Oh man, when I was in high school, I *loved* that part of math where you had to figure out angles and sides of weird shapes. It was definitely my favourite part. I've since forgotten most of the rules, so I'd have to relearn them to do these puzzles, but I kind of want to.
posted by jacquilynne at 12:22 PM on April 12, 2019 [2 favorites]

Goddammit, now I’m trying to do square roots in my head rather than listening to The Talented Mr. Ripley on audiobook. It’s sociopathy vs. geometry in my head now.
posted by GenjiandProust at 1:20 PM on April 12, 2019 [1 favorite]

Granted I ought to be plugging trigonometry apps rather than geometry apps, but if you like this kind of stuff you should check out Euclidea on android and iOS. It's more on the construction side than the calculation side, though.
posted by trig at 1:41 PM on April 12, 2019 [1 favorite]

Coincidentally, just last week with a few minutes to kill and a slide rule on my desk, I thought I'd look up a practice problem to see if I could still use a slide rule. Turns out yes, but the "simple" geometry of the time-speed-distance problem broke my brain enough that I couldn't even figure out what calculations to DO.

Moral: I need to brush up my geometry. These are great.

For the record: A ship steering 10° S. of E. observes a light bearing 40° N. of E. After steaming 8 miles the light bears 15° E. of N. Calculate the distances to the light at the two observations.
posted by ctmf at 6:00 PM on April 12, 2019

Euclidea on android and iOS
Related apps Pythagorea and Pythagorea60 are also good!
posted by soelo at 6:53 PM on April 12, 2019

10.7 miles and 13.9 miles
posted by fitnr at 9:02 PM on April 12, 2019 [1 favorite]

Wow, these look great, but my brain's just bouncing right off them. I think I need to do some like, geometry cardio training.
posted by lucidium at 8:48 AM on April 14, 2019