# Math help, please **URL:** \ **Category:** Factual Questions\ **Created:** [December 13, 2017, 1:55pm UTC](https://boards.straightdope.com/t/math-help-please/804391 "2017-12-13T13:55:19Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 13, 2017, 4:20pm UTC](https://boards.straightdope.com/t/math-help-please/804391/21 "2017-12-13T16:20:38Z")
> [@bibliophage](#): > > It just occurred to me that we should have asked what you meant when you said a nine-inch crust. Is it a crust with a known diameter of nine inches or a crust designed to fit in a 9-inch pie pan? If the latter, it will have to be bigger than 9 inches in diameter, in order to fit up the sides with some left over for edges. The ones I’ve bought in the past were probably at least 12 inches in diameter, maybe 13 or a little more. Assuming 12 inches you should be able to get 16 three-inch circles if you reuse the scraps. True. But … His tarts also have sorta vertical sides. But not as tall. So the simple 9 yarts per pie geometry falls apart some. Overall, we’re about as close to a calculable answer as we can get. It’ll be more than 5 & less than 12. The rest depends on unpredictable details of size, shape,rolling thickness, technique. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [December 13, 2017, 5:37pm UTC](https://boards.straightdope.com/t/math-help-please/804391/22 "2017-12-13T17:37:28Z")
> [@Inner\_Stickler](#): > > According to [this website](https://www.engineeringtoolbox.com/smaller-circles-in-larger-circle-d_1849.html) for a nine inch pie crust, you can get 14 with a 2" diameter, 8 with a 2.5", 5 with a 3", 4 with a 3.5" and 3 with a 4". That website seems to be allowing a little space around the inner circles. That is, it assumes you can’t actually fit three 3" circles across the diameter of a 9" circle. If you ask how many 3" circles fit in a 9" circle it says 5, but if you ask how many 2.999" circles fit in a 9" circle it says 7. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 13, 2017, 6:06pm UTC](https://boards.straightdope.com/t/math-help-please/804391/23 "2017-12-13T18:06:35Z")
It appears that about 1 part in 10^15 is enough slack for it to find the seven-circle solution. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [December 13, 2017, 6:26pm UTC](https://boards.straightdope.com/t/math-help-please/804391/24 "2017-12-13T18:26:15Z")
> [@Chronos](#): > > It appears that about 1 part in 10^15 is enough slack for it to find the seven-circle solution. Whatever it is doing, it does not do a very good job; e.g., I tried packing unit circles in a larger circle of radius 7.7242, and it came up with only 44, whereas the link I gave has 47. ETA it appears to look for some sort of symmetric arrangement… it also does not seem to spend even a few seconds of computation time optimizing the packing ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [December 13, 2017, 6:27pm UTC](https://boards.straightdope.com/t/math-help-please/804391/25 "2017-12-13T18:27:36Z")
I see now that I actually need 3.5" circles. As for pre-made frozen tart shells, they only come precooked and these tarts need to bake. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [December 13, 2017, 6:37pm UTC](https://boards.straightdope.com/t/math-help-please/804391/26 "2017-12-13T18:37:39Z")
> [@DPRK](#): > > Whatever it is doing, it does not do a very good job; e.g., I tried packing unit circles in a larger circle of radius 7.7242, and it came up with only 44, whereas the link I gave has 47. [Here](http://hydra.nat.uni-magdeburg.de/packing/cci/cci.html#Applications) is the “good” link: e.g. it comes up with the 7-circle solution for 9"/3", and of course only 4 for 9"/3.5". It says the latest update was in 2014. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [December 13, 2017, 7:56pm UTC](https://boards.straightdope.com/t/math-help-please/804391/27 "2017-12-13T19:56:43Z")
I’ve made the mince and holy shit is it good. Where the hell has [this stuff](https://www.kingarthurflour.com/recipes/christmas-brandied-mince-tarts-recipe) been all my life? ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [December 13, 2017, 8:33pm UTC](https://boards.straightdope.com/t/math-help-please/804391/28 "2017-12-13T20:33:09Z")
To hell with what they taste like, how many 3" circles did you get? :dubious: ---
**Author:** ![standingwave](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@standingwave](https://boards.straightdope.com/u/standingwave)\ **Post date:** [December 13, 2017, 10:00pm UTC](https://boards.straightdope.com/t/math-help-please/804391/29 "2017-12-13T22:00:11Z")
> [@zoid](#): > > If you don’t want to use the scraps - 7 > Get 7 coins of the same denomination and circle 6 of them around the seventh for a good visual. I concur and that’s a course in materials science talking. That was a fun course. ---
**Author:** ![brainstall](https://avatars.discourse-cdn.com/v4/letter/b/35a633/32.png) [@brainstall](https://boards.straightdope.com/u/brainstall)\ **Post date:** [December 13, 2017, 11:23pm UTC](https://boards.straightdope.com/t/math-help-please/804391/30 "2017-12-13T23:23:21Z")
> [@Chefguy](#): > > I see now that I actually need 3.5" circles. > > As for pre-made frozen tart shells, they only come precooked and these tarts need to bake. Where are you? In my grocery store (Canada), the frozen, unbaked tart shells are near the pie crusts. They even come in the little foil tins. Easy-peasy. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [December 13, 2017, 11:47pm UTC](https://boards.straightdope.com/t/math-help-please/804391/31 "2017-12-13T23:47:57Z")
> [@brainstall](#): > > Where are you? In my grocery store (Canada), the frozen, unbaked tart shells are near the pie crusts. They even come in the little foil tins. Easy-peasy. I checked at two stores and all I saw were the mini puff pastry shells. But I’ve been known to have selective blindness. Well, the mince mix is going to sit for a few days in the fridge, so perhaps I’ll look elsewhere. ---
**Author:** ![araminty](https://avatars.discourse-cdn.com/v4/letter/a/b5e925/32.png) [@araminty](https://boards.straightdope.com/u/araminty)\ **Post date:** [December 14, 2017, 12:32am UTC](https://boards.straightdope.com/t/math-help-please/804391/32 "2017-12-14T00:32:44Z")
I would DEFINITELY recommend making the dough from scratch. American pie crusts are… wrong… for mince pies. They OUGHT to be very short and crumbly, and sweet. Pie crust is too bland and greasy-textured. This Paul Hollywood [recipe](https://www.bbcgoodfood.com/recipes/1813664/mince-pies) looks about right. Just for the dough, obv, since you’ve made the filling. I grabbed a jar of Robertson’s, personally, which I will doctor up. ---
**Author:** ![Patx2](https://avatars.discourse-cdn.com/v4/letter/p/73ab20/32.png) [@Patx2](https://boards.straightdope.com/u/Patx2)\ **Post date:** [December 14, 2017, 12:44am UTC](https://boards.straightdope.com/t/math-help-please/804391/33 "2017-12-14T00:44:03Z")
> [@carnivorousplant](#): > > That’s what I came up with more slowly than you using geometry rather than algebra. 🙂 > > Can the remaining dough be remixed and used? Sorry, I don’t know how many from the original dough, but I did wonder about rolling out the remaining dough and using it. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 14, 2017, 2:04am UTC](https://boards.straightdope.com/t/math-help-please/804391/34 "2017-12-14T02:04:38Z")
@ **Patx2** : As several folks have commented, scraps can be recombined just fine. Especially by somebody named **ChefGuy**. In addition to my caveat in my earlier post I’m going to suggest that the dough for a 9" pie will best be rolled out thicker than for a 3" tart. Said another way, if starting with a prefab crust for a 9" pie, you’ll want to roll it out a bit flatter for 3" tarts. Which will further increase the diameter of the dough sheet and increase the tart yield. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [December 14, 2017, 2:48am UTC](https://boards.straightdope.com/t/math-help-please/804391/35 "2017-12-14T02:48:39Z")
> [@LSLGuy](#): > > @ **Patx2** : As several folks have commented, scraps can be recombined just fine. Especially by somebody named **ChefGuy**. Well, yeah, but a guy named ChefGuy is asking advice. All bets are off. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [December 14, 2017, 4:22am UTC](https://boards.straightdope.com/t/math-help-please/804391/36 "2017-12-14T04:22:07Z")
> [@LSLGuy](#): > > Which will further increase the diameter of the dough sheet and increase the tart yield. This sounds vaguely pornographic. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 14, 2017, 2:22pm UTC](https://boards.straightdope.com/t/math-help-please/804391/37 "2017-12-14T14:22:02Z")
That’s twice this week somebody has accused one of my posts on cooking of being pornographic. Hmmm. ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [December 14, 2017, 2:35pm UTC](https://boards.straightdope.com/t/math-help-please/804391/38 "2017-12-14T14:35:51Z")
NM, I really should have continued reading (I came up with 7). ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [December 18, 2017, 6:03pm UTC](https://boards.straightdope.com/t/math-help-please/804391/39 "2017-12-18T18:03:54Z")
Okay, I bought 12" crusts and had to use a 3.5" cutter. I was able to get eight rounds on the first pass. I had four crusts, so punched out 24 rounds for the mince tarts, then combined all the scraps and made jam tarts out of them. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [December 19, 2017, 2:47am UTC](https://boards.straightdope.com/t/math-help-please/804391/40 "2017-12-19T02:47:13Z")
> [@LSLGuy](#): > > @ **Patx2** : As several folks have commented, scraps can be recombined just fine. Especially by somebody named **ChefGuy**. > > … I hesitate to nitpik (as strange as that sounds, knowing me), because, as mentioned, I’m guessing a guy named Chefguy is a chef guy, and my relationship to baking is …fraught. But scraps of rough or full-on puff pastry degrade after recombination. But mince pies with puff pastry sound lousy. **Chefguy** , congratulations on your yummy new (self) discovery! And get some sleep! [Previous page](https://boards.straightdope.com/t/math-help-please/804391.md?page=1) [Next page](https://boards.straightdope.com/t/math-help-please/804391.md?page=3)