Paula Beardell Krieg likes mathematics. She is also an expert paper folder. Lately, she has been turning pentagons into five-point stars. Here are a couple of her recent twitter posts:
On Monday I wrote about a centered pentagonal number and included a graphic. Paula saw the post and tweeted:
Paula followed through and made my graphic into a beautiful five-point star:
There is nothing like trying to do origami for the first time to make me realize how irregular my pentagon graphic is. I would call my first attempt an epic fail. Sorry, I didn’t take any pictures.
However, before I started folding anything, I made this puzzle for Paula because she inspired me to make a puzzle with a pentagon in it. I needed the puzzle to be at least a 13 x 13 puzzle to get the large pentagon in it, but I decided to make it a 14 x 14 instead. It’s a level 5 so there will be some tricky parts, especially since most of the multiples of 7 in the puzzle are also multiples of 14. Don’t let that stop you from trying to solve it.
Print the puzzles or type the solution in this excel file: 10-factors-951-958
Anyways, after making the puzzle and making my epic fail star, I made this closer-to-regular pentagon on my computer:
I made a star using it. It looked pretty good so I decided to give my graphic of centered pentagonal number 951 a second try. I cut it to make it more regular. Then I followed the directions on the video Paula recommended. My previous folds caused me some problems, but I was able to make something that looks like a star. It isn’t as good as Paula’s, especially on the back, but I’m okay with it. Here are pictures, front and back, of both stars I made (flaws and all):
Now since this is my 956 post, I will share some information about that number:
956 is a palindrome in two other bases:
4C4 BASE 14 (C is 12 base 10) because 4(14²) + 12(14¹) + 4(14⁰) = 956
2H2 BASE 18 (H is 17 base 10) because 2(18²) + 17(18¹) + 2(18⁰) = 956
- 956 is a composite number.
- Prime factorization: 956 = 2 × 2 × 239, which can be written 956 = 2² × 239
- The exponents in the prime factorization are 2 and 1. Adding one to each and multiplying we get (2 + 1)(1 + 1) = 3 × 2 = 6. Therefore 956 has exactly 6 factors.
- Factors of 956: 1, 2, 4, 239, 478, 956
- Factor pairs: 956 = 1 × 956, 2 × 478, or 4 × 239
- Taking the factor pair with the largest square number factor, we get √956 = (√4)(√239) = 2√239 ≈ 30.9192