• Log InLog In
  • Register
Liquid`
Team Liquid Liquipedia
EDT 21:42
CEST 03:42
KST 10:42
  • Home
  • Forum
  • Calendar
  • Streams
  • Liquipedia
  • Features
  • Store
  • EPT
  • TL+
  • StarCraft 2
  • Brood War
  • Smash
  • Heroes
  • Counter-Strike
  • Overwatch
  • Liquibet
  • Fantasy StarCraft
  • TLPD
  • StarCraft 2
  • Brood War
  • Blogs
Forum Sidebar
Events/Features
News
Featured News
Team Liquid Map Contest #22 - The Finalists14[ASL21] Ro16 Preview Pt1: Fresh Flow9[ASL21] Ro24 Preview Pt2: News Flash10[ASL21] Ro24 Preview Pt1: New Chaos0Team Liquid Map Contest #22 - Presented by Monster Energy21
Community News
2026 GSL Season 1 Qualifiers11Maestros of the Game 2 announced32026 GSL Tour plans announced13Weekly Cups (April 6-12): herO doubles, "Villains" prevail1MaNa leaves Team Liquid22
StarCraft 2
General
Blizzard Classic Cup @ BlizzCon 2026 - $100k prize pool 2026 GSL Tour plans announced MaNa leaves Team Liquid Team Liquid Map Contest #22 - The Finalists Weekly Cups (April 6-12): herO doubles, "Villains" prevail
Tourneys
Sparkling Tuna Cup - Weekly Open Tournament GSL CK: More events planned pending crowdfunding 2026 GSL Season 1 Qualifiers Master Swan Open (Global Bronze-Master 2) SEL Doubles (SC Evo Bimonthly)
Strategy
Custom Maps
[D]RTS in all its shapes and glory <3 [A] Nemrods 1/4 players [M] (2) Frigid Storage
External Content
Mutation # 522 Flip My Base The PondCast: SC2 News & Results Mutation # 521 Memorable Boss Mutation # 520 Moving Fees
Brood War
General
Data needed RepMastered™: replay sharing and analyzer site Gypsy to Korea ASL21 General Discussion BGH Auto Balance -> http://bghmmr.eu/
Tourneys
[Megathread] Daily Proleagues Escore Tournament StarCraft Season 2 [ASL21] Ro16 Group A [ASL21] Ro16 Group B
Strategy
Simple Questions, Simple Answers What's the deal with APM & what's its true value Any training maps people recommend? Fighting Spirit mining rates
Other Games
General Games
Nintendo Switch Thread General RTS Discussion Thread Battle Aces/David Kim RTS Megathread Stormgate/Frost Giant Megathread Starcraft Tabletop Miniature Game
Dota 2
The Story of Wings Gaming
League of Legends
G2 just beat GenG in First stand
Heroes of the Storm
Simple Questions, Simple Answers Heroes of the Storm 2.0
Hearthstone
Deck construction bug Heroes of StarCraft mini-set
TL Mafia
Vanilla Mini Mafia Mafia Game Mode Feedback/Ideas TL Mafia Community Thread Five o'clock TL Mafia
Community
General
Things Aren’t Peaceful in Palestine US Politics Mega-thread Russo-Ukrainian War Thread YouTube Thread Canadian Politics Mega-thread
Fan Clubs
The IdrA Fan Club
Media & Entertainment
[Manga] One Piece Anime Discussion Thread [Req][Books] Good Fantasy/SciFi books Movie Discussion!
Sports
2024 - 2026 Football Thread McBoner: A hockey love story Formula 1 Discussion Cricket [SPORT]
World Cup 2022
Tech Support
[G] How to Block Livestream Ads
TL Community
The Automated Ban List
Blogs
Reappraising The Situation T…
TrAiDoS
lurker extra damage testi…
StaticNine
Broowar part 2
qwaykee
Funny Nicknames
LUCKY_NOOB
Iranian anarchists: organize…
XenOsky
ASL S21 English Commentary…
namkraft
Customize Sidebar...

Website Feedback

Closed Threads



Active: 1628 users

Math Puzzle [num18]

Blogs > evanthebouncy!
Post a Reply
evanthebouncy!
Profile Blog Joined June 2006
United States12796 Posts
Last Edited: 2011-02-09 11:14:08
February 09 2011 10:06 GMT
#1
Dear readers!! It has been a long time since I've posted one of these! This one is very cute so hear me out :3

You have a square pizza, and per usual, pizza has crust on the outer perimeter. To simplify, you can think of the crust have no width but only length (so the bend on the corner isn't really a concern to us). Your job is to cut the pizza into 5 equal parts, such that each part has the same amount of area AND the same amount of crust.

In a formal way: Divide a square (with boundary) into 5 equal area parts such that each part contains the same amount of the original boundary. And prove why your method work, of course.


Which tools can we use ? Is that supposed to be a compass and straightedge construction ?

Answer: Nah, that would be more restriction than nessesary.

As usual, put answer in spoilers, and have fun!

edit:
If you have some half-formed idea just post them anyways to keep the thread going, and discussions can be very insightful.

Life is run, it is dance, it is fast, passionate and BAM!, you dance and sing and booze while you can for now is the time and time is mine. Smile and laugh when still can for now is the time and soon you die!
kOre
Profile Blog Joined April 2009
Canada3642 Posts
February 09 2011 10:29 GMT
#2
+ Show Spoiler +
Cut at every 72 degree? Pretty much splitting the pizza into 5 equal parts and they should have equal crust amounts?
http://www.starcraftmecca.net - Founder
evanthebouncy!
Profile Blog Joined June 2006
United States12796 Posts
February 09 2011 10:31 GMT
#3
On February 09 2011 19:29 kOre wrote:
+ Show Spoiler +
Cut at every 72 degree? Pretty much splitting the pizza into 5 equal parts and they should have equal crust amounts?
A: I bolded a letter my question for you

Life is run, it is dance, it is fast, passionate and BAM!, you dance and sing and booze while you can for now is the time and time is mine. Smile and laugh when still can for now is the time and soon you die!
kOre
Profile Blog Joined April 2009
Canada3642 Posts
Last Edited: 2011-02-09 10:33:14
February 09 2011 10:32 GMT
#4
+ Show Spoiler +
Like this except actually at every 72 degree angle.

[image loading]
http://www.starcraftmecca.net - Founder
RisingTide
Profile Joined December 2008
Australia769 Posts
Last Edited: 2011-02-09 10:50:51
February 09 2011 10:33 GMT
#5
Got it but I have no idea how to represent it :D

Nvm: got an idea.
+ Show Spoiler +

Cheater
+ Show Spoiler +

[image loading]


Basically consider it a 10x10 grid, and divide into sections with a perimeter 8 and area 20.

kaleidoscope
Profile Blog Joined December 2008
Singapore2887 Posts
February 09 2011 10:35 GMT
#6
On February 09 2011 19:29 kOre wrote:
+ Show Spoiler +
Cut at every 72 degree? Pretty much splitting the pizza into 5 equal parts and they should have equal crust amounts?


+ Show Spoiler +
the corner (crust)will not be of equal area isnt it?
대지따라 돌린게 시간이다.. 흘러가고 돌아오지도 않고..
Ivs
Profile Joined January 2008
Australia139 Posts
February 09 2011 10:36 GMT
#7
+ Show Spoiler +

Split the perimeter into 5 equal chunks arbitratily (and none of the chunks are disjoint). Join the 5 boundary points towards the centre of the square with straight lines. The 5 resulting areas satisfy the criteria, since each chunk can be split up into at most 2 triangles, with base on the boundary and a height of 1/2. So each area is 1/2*1/2*4/5=1/5 as required.
endy
Profile Blog Joined May 2009
Switzerland8970 Posts
February 09 2011 10:40 GMT
#8
Which tools can we use ? Is that supposed to be a compass and straightedge construction ?
ॐ
kOre
Profile Blog Joined April 2009
Canada3642 Posts
February 09 2011 10:40 GMT
#9
+ Show Spoiler +
The SQUARE pizza can be treated as a RECTANGULAR pizza with no crust on the left and right side and only crust on the top and bottom. Cut the slices vertically and it should be easy to make them even? Rectangle is fatter and shorter while the square is skinnier and taller making them even? [image loading]
http://www.starcraftmecca.net - Founder
Ivs
Profile Joined January 2008
Australia139 Posts
February 09 2011 10:48 GMT
#10
On February 09 2011 19:36 Ivs wrote:
+ Show Spoiler +

Split the perimeter into 5 equal chunks arbitratily (and none of the chunks are disjoint). Join the 5 boundary points towards the centre of the square with straight lines. The 5 resulting areas satisfy the criteria, since each chunk can be split up into at most 2 triangles, with base on the boundary and a height of 1/2. So each area is 1/2*1/2*4/5=1/5 as required.


+ Show Spoiler +
Oh hey this works for any number of pizza eaters, cool!
SOB_Maj_Brian
Profile Blog Joined September 2008
United States522 Posts
February 09 2011 11:10 GMT
#11
Riser doesn't the middle piece of your solution have 8 units of original crust and all the remaining ones have 7? Or am I missing something here?
evanthebouncy!
Profile Blog Joined June 2006
United States12796 Posts
Last Edited: 2011-02-09 11:17:23
February 09 2011 11:13 GMT
#12
On February 09 2011 19:48 Ivs wrote:
Show nested quote +
On February 09 2011 19:36 Ivs wrote:
+ Show Spoiler +

Split the perimeter into 5 equal chunks arbitratily (and none of the chunks are disjoint). Join the 5 boundary points towards the centre of the square with straight lines. The 5 resulting areas satisfy the criteria, since each chunk can be split up into at most 2 triangles, with base on the boundary and a height of 1/2. So each area is 1/2*1/2*4/5=1/5 as required.


+ Show Spoiler +
Oh hey this works for any number of pizza eaters, cool!


+ Show Spoiler +


Life is run, it is dance, it is fast, passionate and BAM!, you dance and sing and booze while you can for now is the time and time is mine. Smile and laugh when still can for now is the time and soon you die!
evanthebouncy!
Profile Blog Joined June 2006
United States12796 Posts
February 09 2011 11:16 GMT
#13
On February 09 2011 20:10 SOB_Maj_Brian wrote:
Riser doesn't the middle piece of your solution have 8 units of original crust and all the remaining ones have 7? Or am I missing something here?


+ Show Spoiler +

The corner counts twice, so the remaining ones do indeed have 8 perimeters.
Life is run, it is dance, it is fast, passionate and BAM!, you dance and sing and booze while you can for now is the time and time is mine. Smile and laugh when still can for now is the time and soon you die!
HaNdFisH
Profile Blog Joined February 2010
Australia119 Posts
Last Edited: 2011-02-09 11:56:36
February 09 2011 11:29 GMT
#14
Pieces don't have to be the same shape? Just equal amount of outer perimeter taken from edge (inner perimeter okay) and same area?

+ Show Spoiler +

In that case take a triangle out of each side of the pizza (long base edge along crust side) of base 4/5, height 1/2. (this is for square pizza side length 1, can scale to whatever side length). This results in 4 pieces of base (crust) 4/5 units each, leaving 4/5 units of crust for the remaining piece. Each of these pieces has area 1/5 square units, leaving 1/5 for the remaining piece.

*edit* hmm, remaining piece is cut by the others so this doesn't work :<, i guess it depends if you allow the pizza to be counted as one piece when connected by a single point
pksens
Profile Joined July 2010
United Kingdom156 Posts
February 09 2011 11:35 GMT
#15
+ Show Spoiler +
I like drawing 5 pointed stars so I could roughly get 5 points evenly split inside a square. You can then have a cut from the center point through each point or half way point (prefer half way for neatness!)
blue001
Profile Joined January 2009
106 Posts
February 09 2011 11:36 GMT
#16
Ivs - You are smart. Congratuations for the solution
mcht
Profile Joined December 2009
Germany201 Posts
Last Edited: 2011-02-09 11:44:26
February 09 2011 11:44 GMT
#17
+ Show Spoiler +
[image loading]
evanthebouncy!
Profile Blog Joined June 2006
United States12796 Posts
February 10 2011 01:14 GMT
#18
On February 09 2011 20:36 blue001 wrote:
Ivs - You are smart. Congratuations for the solution


yeah he's fcken pro lol it took me 3 days and sleepless dreams hahHAha, i literally jizzed myself when I solved it. Then my friend did it in like 1 minute I was like .____.
Life is run, it is dance, it is fast, passionate and BAM!, you dance and sing and booze while you can for now is the time and time is mine. Smile and laugh when still can for now is the time and soon you die!
JeeJee
Profile Blog Joined July 2003
Canada5652 Posts
Last Edited: 2011-02-10 02:28:11
February 10 2011 02:06 GMT
#19
+ Show Spoiler +

seems pretty simple which means i must be misunderstanding it
but here's what i got (based on the android game sliceit)
so for simplicity's sake let's say its a 5x5 pizza
divide border into 5 cuts, 4 squares long each
from there, make cuts such that each piece is 5 squares in area?
[image loading]

O-o
edit:
come to think of it, you can just cut straight to centre of pizza. should be pretty trivial to see why
(\o/)  If you want it, you find a way. Otherwise you find excuses. No exceptions.
 /_\   aka Shinbi (requesting a name change since 27/05/09 ☺)
Please log in or register to reply.
Live Events Refresh
Replay Cast
00:00
Code For Giants Cup #29
Liquipedia
BSL
19:00
RO32 Group D
StRyKeR vs rasowy
Artosis vs Aether
JDConan vs OyAji
Hawk vs izu
LiquipediaDiscussion
[ Submit Event ]
Live Streams
Refresh
StarCraft 2
RuFF_SC2 183
ProTech164
StarCraft: Brood War
GuemChi 5987
Artosis 849
Britney 647
ggaemo 65
NaDa 33
Dota 2
monkeys_forever811
NeuroSwarm127
League of Legends
JimRising 660
Super Smash Bros
hungrybox625
Heroes of the Storm
Khaldor163
Other Games
gofns24251
tarik_tv17703
summit1g15214
C9.Mang0365
sgares212
Maynarde151
ViBE121
Mew2King37
Organizations
Other Games
gamesdonequick678
BasetradeTV251
StarCraft 2
Blizzard YouTube
StarCraft: Brood War
BSLTrovo
sctven
[ Show 14 non-featured ]
StarCraft 2
• Hupsaiya 104
• Mapu6
• CranKy Ducklings SOOP3
• AfreecaTV YouTube
• intothetv
• Kozan
• IndyKCrew
• LaughNgamezSOOP
• Migwel
• sooper7s
StarCraft: Brood War
• BSLYoutube
• STPLYoutube
• ZZZeroYoutube
Other Games
• Scarra1166
Upcoming Events
Replay Cast
7h 18m
Wardi Open
8h 18m
Afreeca Starleague
8h 18m
Bisu vs Ample
Jaedong vs Flash
Monday Night Weeklies
14h 18m
RSL Revival
1d
GSL
1d 6h
Afreeca Starleague
1d 8h
Barracks vs Leta
Royal vs Light
WardiTV Map Contest Tou…
1d 9h
RSL Revival
2 days
Replay Cast
2 days
[ Show More ]
The PondCast
3 days
KCM Race Survival
3 days
WardiTV Map Contest Tou…
3 days
CranKy Ducklings
3 days
Escore
4 days
RSL Revival
4 days
WardiTV Map Contest Tou…
5 days
Universe Titan Cup
5 days
Rogue vs Percival
Ladder Legends
5 days
uThermal 2v2 Circuit
5 days
BSL
5 days
Sparkling Tuna Cup
6 days
WardiTV Map Contest Tou…
6 days
Ladder Legends
6 days
BSL
6 days
Replay Cast
6 days
Liquipedia Results

Completed

Escore Tournament S2: W3
RSL Revival: Season 4
NationLESS Cup

Ongoing

BSL Season 22
ASL Season 21
CSL 2026 SPRING (S20)
IPSL Spring 2026
KCM Race Survival 2026 Season 2
StarCraft2 Community Team League 2026 Spring
WardiTV TLMC #16
Nations Cup 2026
IEM Rio 2026
PGL Bucharest 2026
Stake Ranked Episode 1
BLAST Open Spring 2026
ESL Pro League S23 Finals
ESL Pro League S23 Stage 1&2
PGL Cluj-Napoca 2026
IEM Kraków 2026

Upcoming

Escore Tournament S2: W4
Acropolis #4
BSL 22 Non-Korean Championship
CSLAN 4
Kung Fu Cup 2026 Grand Finals
HSC XXIX
uThermal 2v2 2026 Main Event
2026 GSL S2
RSL Revival: Season 5
2026 GSL S1
XSE Pro League 2026
IEM Cologne Major 2026
Stake Ranked Episode 2
CS Asia Championships 2026
IEM Atlanta 2026
Asian Champions League 2026
PGL Astana 2026
BLAST Rivals Spring 2026
TLPD

1. ByuN
2. TY
3. Dark
4. Solar
5. Stats
6. Nerchio
7. sOs
8. soO
9. INnoVation
10. Elazer
1. Rain
2. Flash
3. EffOrt
4. Last
5. Bisu
6. Soulkey
7. Mini
8. Sharp
Sidebar Settings...

Advertising | Privacy Policy | Terms Of Use | Contact Us

Original banner artwork: Jim Warren
The contents of this webpage are copyright © 2026 TLnet. All Rights Reserved.